Accessory Structures of the Skin

Accessory Structures of the Skin tài liệu, giáo án, bài giảng , luận văn, luận án, đồ án, bài tập lớn về tất cả các lĩnh...

THE STRUCTURES OF THE SENTENCES IN ENGLISH 1.Would you like + Vinf … ? 2. Would you mind + V-ing….? Would you mind if + clause (not true) 3. You had better + V- inf - would rather + Vinf ….(than) - prefer to inf => prefer sth to sth 4. too + adj + for O + to inf 5. adj+enough +for O + to inf 6. so +adj+ that + clause - such (a/an) ….N + that + clause 7. It’s + adj+ to inf * have a chance + to inf 8. I know + Noun Clause (Wh-w + S+V ) 9. Comparison of adjective. - as + adj + as => not so/as +adj+as - better +than => more + adj +than - the tallest in many => The most +adj 10. advice/ tell/ ask/ request + sb + to inf - have/ beg + sb+ Vinf 11. Wish – present=> S+ V-ed/ V2 (be = WERE) - past => S+ had +PP… - future => S +would + Vinf >< S + hope + will+Vinf 12. Unless = If not 13. That is the first time + past clause => S + present perfect + since/ for + time 14. If only S+ would Vinf => If only you would stop complaining! 15. Tag-question: I am a teacher, aren’t I? You’re listening to me, are you? 16. so am I/ so do I = I am, too/ I do,too. - I am not either/ I don’t either = Neither am I / Neither do I . 17. not only…but also…as well 18. One of + plural noun 19. all of us = almost us 20. keep + V-ing = continue to inf 21. used to + V inf (habit in the past) => am/is/are +used to +V-ing (habit in the present) 22. Make sb +to inf She laughed because of the clowns => The clowns made her laugh. 23. Would you go to London if you could? => I would If I could, but I don’t think I can. If I could = If I were able to. 24. go + V-ing 25. Relative Adverbs Where, When - Teacher’s day when students show their gratitude to their teachers. - Mother’s day when children show their love to their mothers. - Viet Nam where we were born - Hoa Thinh where I was born is a smaal village. 26. Call/ choose/ consider/ select + O+ CO (complement object) - We choose Nam the monitor. - We call him Tommy. 27. Miêu tả sự vật ngày càng phát triển. Form: - The river gets bigger and bigger - The girl becomes more and more intelligent. 28. The direct speech and reported speech. - Mary said, “I will come back this department store tomorrow” => Mary said that she would come back that department store the following day. - Mary said to me, “I will come back this department store tomorrow” => Mary told me that she would come back that department store the following day. Question: - “what is your name?” the teacher asked me =>The teacher asked (me)what my name was. Note: She said, “Are you thirsty, Mary?”  She asked Mary if (whether) she was thirsty. 1. Change in tense Direct speech Reported speech Present simple past simple Present Progressive past Progressive Future simple would + verb Can/ may could/ might 2. Change in adverbs and articles this → that these → those here → there now → then tomorrow → the following day today → that day Direct speech Reported speech Present simple … progressive Future simple can/ may must had to needn’t didn’t have to II. Reported questions: → Yes/ No questions (if/ whether ) Notes: S + asked ( O) Wanted to know + If/ whether + Wondered S + V adj + er and +adj + er more and more +adj yesterday → the day before… Example 1: S1: Do you like pop music? S2: She asked me if/ whether I liked pop music. Example 2: S1: Where do you live? S2: She asked me where I lived. 29. Have/ beg (passive) - S + have + sth+ passive… 30 It is said that = People say that 31. Compare: (hai sự vật ngày càng phát triển song song) Form: Short adj: Long adj: 32. V + preposition be amazed at / be amused at/ be delighted at/ be interested in/ take part in/ Take care of = look after be bored with/ be fed up with/ be tired of/ tell sb about st/ get rid of/ give up/ depend on/ be different Accessory Structures of the Skin Accessory Structures of the Skin Bởi: OpenStaxCollege Accessory structures of the skin include hair, nails, sweat glands, and sebaceous glands These structures embryologically originate from the epidermis and can extend down through the dermis into the hypodermis Hair Hair is a keratinous filament growing out of the epidermis It is primarily made of dead, keratinized cells Strands of hair originate in an epidermal penetration of the dermis called the hair follicle The hair shaft is the part of the hair not anchored to the follicle, and much of this is exposed at the skin’s surface The rest of the hair, which is anchored in the follicle, lies below the surface of the skin and is referred to as the hair root The hair root ends deep in the dermis at the hair bulb, and includes a layer of mitotically active basal cells called the hair matrix The hair bulb surrounds the hair papilla, which is made of connective tissue and contains blood capillaries and nerve endings from the dermis ([link]) 1/8 Accessory Structures of the Skin Hair Hair follicles originate in the epidermis and have many different parts Just as the basal layer of the epidermis forms the layers of epidermis that get pushed to the surface as the dead skin on the surface sheds, the basal cells of the hair bulb divide and push cells outward in the hair root and shaft as the hair grows The medulla forms the central core of the hair, which is surrounded by the cortex, a layer of compressed, keratinized cells that is covered by an outer layer of very hard, keratinized cells known as the cuticle These layers are depicted in a longitudinal cross-section of the hair follicle ([link]), although not all hair has a medullary layer Hair texture (straight, curly) is determined by the shape and structure of the cortex, and to the extent that it is present, the medulla The shape and structure of these layers are, in turn, determined by the shape of the hair follicle Hair growth begins with the production of keratinocytes by the basal cells of the hair bulb As new cells are deposited at the hair bulb, the hair shaft is pushed through the follicle toward the surface Keratinization is completed as the cells are pushed to the skin surface to form the shaft of hair that is externally visible The external hair is completely dead and composed entirely of keratin For this reason, our hair does not have sensation Furthermore, you can cut your hair or shave without damaging the hair structure because the cut is superficial Most chemical hair removers also act superficially; however, electrolysis and yanking both attempt to destroy the hair bulb so hair cannot grow 2/8 Accessory Structures of the Skin Hair Follicle The slide shows a cross-section of a hair follicle Basal cells of the hair matrix in the center differentiate into cells of the inner root sheath Basal cells at the base of the hair root form the outer root sheath LM × (credit: modification of work by “kilbad”/Wikimedia Commons) The wall of the hair follicle is made of three concentric layers of cells The cells of the internal root sheath surround the root of the growing hair and extend just up to the hair shaft They are derived from the basal cells of the hair matrix The external root sheath, which is an extension of the epidermis, encloses the hair root It is made of basal cells at the base of the hair root and tends to be more keratinous in the upper regions The glassy membrane is a thick, clear connective tissue sheath covering the hair root, connecting it to the tissue of the dermis The hair follicle is made of multiple layers of cells that form from basal cells in the hair matrix and the hair root Cells of the hair matrix divide and differentiate to form the layers of the hair Watch this video to learn more about hair follicles Hair serves a variety of functions, including protection, sensory input, thermoregulation, and communication For example, hair on the head protects the skull from the sun The hair in the nose and ears, and around the eyes (eyelashes) defends the body by trapping and excluding dust particles that may contain allergens and microbes Hair of the eyebrows prevents sweat and other particles from dripping into and bothering the eyes Hair also has a sensory function due to sensory innervation by a hair root plexus surrounding the base of each hair follicle Hair is extremely sensitive to air movement or 3/8 Accessory Structures of the Skin other disturbances in the environment, much more so than the skin surface This feature is also useful for the detection of the presence of insects or other potentially damaging substances on the skin surface Each hair root is connected to a smooth muscle called the arrector pili that contracts in response to nerve signals from the sympathetic nervous system, making the external hair shaft “stand up.” The primary purpose for this is to trap a layer of air to add insulation This is visible in humans as goose bumps and even ...Crystal structures of the regulatory subunit of Thr-sensitive aspartate kinase from Thermus thermophilus Ayako Yoshida 1 , Takeo Tomita 1 , Hidetoshi Kono 2 , Shinya Fushinobu 3 , Tomohisa Kuzuyama 1 and Makoto Nishiyama 1,4 1 Biotechnology Research Center, The University of Tokyo, Japan 2 Computational Biology Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Kyoto, Japan 3 Department of Biotechnology, The University of Tokyo, Japan 4 RIKEN SPring-8 Center, Hyogo, Japan Aspartate kinase (AK; EC 2.7.2.4) is an enzyme that catalyzes the first committed step, the phosphorylation of the c-carboxyl group of aspartate, of the biosynthetic pathway of the aspartic acid group amino acids Lys, Thr, Ile, and Met, in microorganisms and plants. AK is classified into two groups according to subunit orga- nization: homo-oligomer or heterotetramer. AK from Thermus thermophilus (TtAK), AK from C. glutami- cum (CgAK) and AKII from Bacillus subtilis (BsAKII) are heterotetramers containing equimolar amounts of a-subunits and b-subunits [1–3], whereas AKIII from Escherichia coli (EcAKIII), AKI from Arabidopsis thaliana and AK from Methanococcus jannaschii (MjAK) are homo-oligomers of identical subunits [4–6]. AK of the a 2 b 2 type is encoded by in-frame overlapping genes, so that the amino acid sequence of the b-subunit is identical to about 160 amino acids of the C-terminus of the a-subunit. As seen in other enzymes involved in the first step in amino acid bio- synthesis, AK is regulated through feedback inhibition Keywords ACT domain; allosteric regulation; crystal structure; thermostability; threonine biosynthesis Correspondence M. Nishiyama, Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan Fax: +81 3 5841 8030 Tel: +81 3 5841 3074 E-mail: umanis@mail.ecc.u-tokyo.ac.jp (Received 3 November 2008, revised 10 March 2009, Accepted 31 March 2009) doi:10.1111/j.1742-4658.2009.07030.x Crystal structures of the regulatory subunit of Thr-sensitive aspartate kinase (AK; EC 2.7.2.4) from Thermus thermophilus (TtAKb) were deter- mined at 2.15 A ˚ in the Thr-bound form (TtAKb-Thr) and at 2.98 A ˚ in the Thr-free form (TtAKb-free). Although both forms are crystallized as dimers, the contact surface area of the dimer interface in TtAKb-free (3200 A ˚ 2 ) is smaller than that of TtAKb-Thr (3890 A ˚ 2 ). Sedimentation equilibrium analyzed by ultracentrifugation revealed that TtAKb is present in equilibrium between a monomer and dimer, and that Thr binding shifts the equilibrium to dimer formation. In the absence of Thr, an outward shift of b-strands near the Thr-binding site (site 1) and a concomitant loss of the electron density of the loop region between b3 and b4 near the Thr- binding site are observed. The mechanism of regulation by Thr is discussed on the basis of the crystal structures. TtAKb has higher thermostability than the regulatory subunit of Corynebacterium glutamicum AK, with a dif- ference in denaturation temperature (T m )of40°C. Comparison of the crystal structures of TtAKb and the regulatory subunit of C. glutamicum AK showed that the well-packed hydrophobic core and high Pro content in loops contribute to the high thermostability of TtAKb. Abbreviations AK, aspartate kinase; BsAKII, aspartate kinase II from Bacillus subtilis; CgAK, aspartate kinase from Corynebacterium glutamicum; CgAKb, regulatory subunit of The structures of the lipooligosaccharide and capsule polysaccharide of Campylobacter jejuni genome sequenced strain NCTC 11168 Frank St. Michael, Christine M. Szymanski, Jianjun Li, Kenneth H. Chan, Nam Huan Khieu, Suzon Larocque, Warren W. Wakarchuk, Jean-Robert Brisson and Mario A. Monteiro Institute for Biological Sciences, National Research Council of Canada, Ottawa, Canada Campylobacter jejuni infections are one of the leading causes of human gastroenteritis and are suspected of being a pre- cursor to Guillain–Barre ´ and Miller–Fisher syndromes. Recently, the complete genome sequence of C. jejuni NCTC 11168 was described. In this study, the molecular structure of the lipooligosaccharide and capsular polysaccharide of C. jejuni NCTC 11168 was investigated. The lipooligosac- charide was shown to exhibit carbohydrate structures anal- ogous to the GM1a and GM2 carbohydrate epitopes of human gangliosides (shown below): The high M r capsule polysaccharide was composed of b- D -Ribp, b- D -GalfNAc, a- D -GlcpA6(NGro), a uronic acid amidated with 2-amino-2-deoxyglycerol at C-6, and 6-O-methyl- D -glycero-a- L -gluco-heptopyranose as a side- branch (shown below): The structural information presented here will aid in the identification and characterization of specific enzymes that are involved in the biosynthesis of these structures and may lead to the discovery of potential therapeutic targets. In addition, the correlation of carbohydrate structure with gene complement will aid in the elucidation of the role of these surface carbohydrates in C. jejuni pathogenesis. Keywords: lipooligosaccharide; capsule; electron spray ionization mass spectrometry; high-resolution magic angle spinning NMR; heptose. In humans, Campylobacter jejuni infection often gives rise to enteritis and, in some regions, this Gram-negative bacterium surpasses Salmonella, Shigella and Escherichia as the primary cause of gastrointestinal disease [1,2]. Moreover, C. jejuni infections have been linked to the more severe clinical outcomes caused by Guillain–Barre ´ [3,4] and Miller–Fisher syndromes [5]. The subsequent paralysis observed in Guillain-Barre ´ and Miller–Fisher syndromes is thought to be an autoimmune reaction due to molecular mimicry of gangliosides by C. jejuni lipooligosaccharides (LOS) [6,7]. In the pioneering studies carried out by Aspinall and coworkers on the cell-surface carbohydrates from Campylobacter species, it was observed that insoluble gels from phenol-water extractions of bacterial cells yielded mainly low M r LOS, with core oligosaccharide linked to lipid A, and the aqueous phases from such extractions furnished high M r glycans with extended polymers with no attachment to lipid A as seen in the teichoic acid-like P/PEtn GM1a GM2 fl 6 b-Gal-(1fi3)- b- D -GalNAc-(1fi4)-b- D -Gal-(1 fi3)-b- D -Gal-(1fi3)- L -a- D -Hep-(1fi3)- L -a- D -Hep-(1fi5)Kdo 32 2 4 ›› › › 21 1 1 a-Neu5Ac a- D -Gal b- D -Glc b- D -Glc 6-O-Me- D -a- L -glcHepp 1 fl 3 fi2)-b- D -Ribf-(1-5)-b- D -Galf NAc-(1-4)-a- D -GlcpA6(NGro)-(1fi 0 B B B B @ 0 B B B B @ 1 C C C C A Correspondence to J R. Brisson, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Canada, K1A 0R6. Fax: + 1 613 952 9092, Tel.: + 1 613 990 3244, E-mail: jean-robert.brisson@nrc.ca; M. Monteiro, Wyeth Vaccines Research, 211 Bailey Road, West Henrietta, NY, 14586, USA. Fax: + 1 585 273 751, Tel.: + 1 585 273 7667, E-mail: Monteim@wyeth.com Abbreviations: CE, capillary electrophoresis; ESI-MS, electron spray ionization mass spectrometry; FAB, Crystal structures of the apo form of b-fructofuranosidase from Bifidobacterium longum and its complex with fructose Anna Bujacz, Marzena Jedrzejczak-Krzepkowska, Stanislaw Bielecki, Izabela Redzynia and Grzegorz Bujacz Institute of Technical Biochemistry, Faculty of Biotechnology and Food Sciences, Technical University of Lodz, Poland Introduction Bifidobacteria are found in human and animal gastro- intestinal tracts, as well as in the oral cavity and the vagina [1]. They are among the first bacteria that colo- nize the sterile digestive system of newborns and they become predominant micro-organisms ($ 95% of the colonic flora) in breast-fed infants [2]. In infants, the most frequently detected bifidobacteria species are Bifidobacterium breve, Bifidobacterium infan- tis, Bifidobacterium bifidum and Bifidobacterium longum. The latter one also inhabits the intestines of adults, despite the fact that the composition of bifidobacterial species changes and the amount of bifidobacteria decreases with age [3–6]. They are Gram-positive, nons- porulating and nonmotile rods, classified as lactic acid bacteria, due to their ability to anaerobically ferment carbohydrates [7,8]. These bacteria are known as micro- Keywords b-fructofuranosidase; Bifidobacterium longum; crystal structure; glycoside hydrolase family GH32; lactic acid bacteria Correspondence A. Bujacz, Institute of Technical Biochemistry, Faculty of Biotechnology and Food Sciences, Technical University of Lodz, Stefanowskiego 4 ⁄ 10, 90-924 Lodz, Poland Fax: 48 42 6366618 Tel: 48 42 6313494 E-mail: anna.bujacz@p.lodz.pl (Received 13 January 2011, revised 25 February 2011, accepted 15 March 2011) doi:10.1111/j.1742-4658.2011.08098.x We solved the 1.8 A ˚ crystal structure of b-fructofuranosidase from Bifido- bacterium longum KN29.1 – a unique enzyme that allows these probiotic bacteria to function in the human digestive system. The sequence of b-fruc- tofuranosidase classifies it as belonging to the glycoside hydrolase family 32 (GH32). GH32 enzymes show a wide range of substrate specificity and different functions in various organisms. All enzymes from this family share a similar fold, containing two domains: an N-terminal five-bladed b-propeller and a C-terminal b-sandwich module. The active site is located in the centre of the b-propeller domain, in the bottom of a ‘funnel’. The binding site, )1, responsible for tight fructose binding, is highly conserved among the GH32 enzymes. Bifidobacterium longum KN29.1 b-fructofura- nosidase has a 35-residue elongation of the N-terminus containing a five- turn a-helix, which distinguishes it from the other known members of the GH32 family. This new structural element could be one of the functional modifications of the enzyme that allows the bacteria to act in a human digestive system. We also solved the 1.8 A ˚ crystal structure of the b-fruc- tofuranosidase complex with b- D-fructose, a hydrolysis product obtained by soaking apo crystal in raffinose. Database Coordinates and structure factors have been deposited in the Protein Data Bank under acces- sion codes: 3PIG and 3PIJ Structured digital abstract l b-fructofuranosidase binds to b-fructofuranosidase by x-ray crystallography (View interaction) Abbreviation GH32, glycoside hydrolase family 32. 1728 FEBS Journal 278 (2011) 1728–1744 ª 2011 The Authors Journal compilation ª 2011 FEBS organisms that [...]... from the knee of a 10-year-old boy 6 El Gammal et al FIGURE 6 Silicon replica from the dorsum of the hand (base of the third finger) of a 30-year-old woman (A) Extension and (B) flexion Comparison of newborn and adult skin shows that the specific patterns described above are genetically determined and present from birth With growth of the body, the distances between the lines enlarge proportionally and their... biopsies in sodium bromide, the primary lines remain visible on the surface of the papillary dermis They separate groups of about 20 to 50 dermal papillae (1,28) After injuries that destroy the dermal papillae and lead to scar formation, the glyphic pattern of the surface is no longer present FIGURE 7 Silicon replica from the dorsum of the hand (base of the third finger) of a threemonth-old child (A)... Glyphic patterns are peculiar to the human surface What purpose do they serve? Several hypotheses have been offered To us, the most likely seems the theory of Schellander and Headington that ‘ the creases and indentations found in the resting skin act as prefolds which determine the exact points of flexion and extension when the stratum corneum is deformed’’ (23) In short, they are pleats that allow deformations... Understanding the Interaction of Light with Aging Skin 424 Changes in the Expression and Presentation of Melanin, Hemoglobin, Collagen, and in Surface Topography with Age 425 The Effect of Chromophore and Topography Changes in Aging Skin Upon Perception of Age, Health, and Beauty 428 The Core Principle of Effective Digital Imaging— Reproducibility 429 The Practical Use of Imaging of Aging Skin. .. visualization of surfaces Because we cannot look inside, we define objects through their interfaces This, of course, holds true for human skin The interface, which meets our eyes, is the stratum corneum, the dead outer layer of the epidermis, composed of flattened horny cells, which are constantly being shed Still, the physical state of the stratum corneum often reflects changes that have occurred below in the. .. Imaging Approaches 221 Nikiforos Kollias Introduction 221 The Interaction of Light with the Skin 222 Macroimaging of the Skin 228 Integrated Imaging: Mode—Wavelength 229 Polarized Light Imaging of Skin 231 Fluorescence Imaging of the Skin with Excitation in the Ultraviolet-A Radiation or the Blue 238 Wavelength Integration 244 Suggested Reading 246 17... stripping with staining reveals the shape, the overlapping edges, and the nuclear remnants of these cells (Fig 2) Viewing the specimens by phase-contrast microscopy gives an idea of their inner contents, namely the fibrous cytoskeleton When the surface is smooth, monolayers of corneocytes come off by stripping In scaling conditions, thick clusters of corneocytes stick to the tape In hyperkeratotic ... present, the medulla The shape and structure of these layers are, in turn, determined by the shape of the hair follicle Hair growth begins with the production of keratinocytes by the basal cells of the. .. pushed to the surface as the dead skin on the surface sheds, the basal cells of the hair bulb divide and push cells outward in the hair root and shaft as the hair grows The medulla forms the central.. .Accessory Structures of the Skin Hair Hair follicles originate in the epidermis and have many different parts Just as the basal layer of the epidermis forms the layers of epidermis