(n.) Something used to secure and hold in place something else, as a long fiat-headed nail, a catch a hook, a clinch, a clamp, etc.; hence, a support.
(n.) A conical or branching body, by which a seaweed is attached to its support, and differing from a root in that it is not specially absorbent of moisture.
Example Sentences:
(1) In addition, distribution of lead and cadmium varied within the individual producer (Fucus vesiculosus) in such a way that the holdfast exhibited the highest concentration followed by the apcial tip and the branches of the first dichotomy was the lowest.
(2) Thus, we propose that the attachment of the holdfast to the cell is a true adhesion process and that the stalk tip and base of the flagellum must have compositions distinctly different from that of the remainder of the caulobacter cell surface.
(3) Upon closer examination, they were distinguishable on the basis of protein band profiles on polyacrylamide gel electrophoresis, gross colony characteristics, or holdfast composition or by DNA restriction fragment length polymorphism analysis with flagellin and S-layer gene probes.
(4) The mutant could also attach to the discarded holdfast produced by a shedding mutant.
(5) Also, attachment to the cell is accomplished by bond formations that occur not only at the time of holdfast production.
(6) One class of mutants made a normal holdfast by all available criteria, yet the attachment to the cell was very weak, such that the holdfast was readily shed.
(7) Once attached the bacterium appears to undergo a complex life cycle which involves the development of a long filament divided into a number of segments within which holdfasts or spores are formed.
(8) Deletion and complementation analysis of the hfaAB locus revealed two genes in a single operon; both were required for holdfast attachment to the cell.
(9) The structure and distribution of papillae suggest that the ventral sucker likely functions as a holdfast organ and the oral sucker as a probing organ involved in feeding.
(10) The formation of the holdfast, cell walls and septa is followed.
(11) Within each mother cell two new holdfast segments developed.
(12) The paunch epithelium was densely colonized by bacteria, many of which possessed holdfast elements that secured them tightly to this tissue and to other bacterial cells.
(13) Caulobacters attach to surfaces in the environment via their holdfasts, attachment organelles located at the base of the flagellum in swarmer cells and later at the end of the cellular stalk in the stalked cells which develop from the swarmer cells.
(14) Taken together, the data support the interpretation that there is a specialized attachment site for the holdfast at the base of the flagellum which later becomes the end of the stalk, but not a specialized region of the holdfast for attachment to this site.
(15) The bacterium is attached to the epithelial cell by a special segment (holdfast) and causes specific changes in the epithelial cell at the site of attachment.
(16) This was unexpected, since holdfast deficiency is often a characteristic of pleiotropic mutants obtained when selecting for loss of other polar structures.
(17) This information suggests that the protein encoded by the hfaA locus may have a direct role in the attachment of the holdfast to the cell, whereas hfaB may be involved in the positive regulation of hfaC.
(18) A single prostheca extends from one pole of mature cells, and cells attach to various substrata by means of a holdfast located at the distal tip of the appendage.
(19) However, there was no subsequent division, or flagellum or holdfast synthesis.
(20) Alternately, in some filaments, newly formed but not yet released holdfasts were converted into endospores, which were released in the same manner as holdfasts, presumably to spread the bacterial colony to other members of the rodent population.
Sessile
Definition:
(a.) Attached without any sensible projecting support.
(a.) Resting directly upon the main stem or branch, without a petiole or footstalk; as, a sessile leaf or blossom.
(a.) Permanently attached; -- said of the gonophores of certain hydroids which never became detached.
Example Sentences:
(1) These 87 adenomas were mostly (79%) under 5 mm in diameter, sessile (89%) and histologically tubular with slight dysplasia (95%).
(2) We classify the hernias as pedunculated or sessile, with associated factors such as viability of herniated brain, infection, CSF leak, and neurologic complications.
(3) Two hundred and fifty colonoscopy procedures were reviewed, revealing 87 sessile colon polyps ranging from 0.5-6.0 cm.
(4) Traditional elastomeric impression materials, four recently developed "hydrophilic" silicones and a hydrocolloid have been tested for their accuracy of reproduction by use of indirect measurements via plaster dies and for their wettability by means of the sessile drop method.
(5) In flow-through microcosms RC-4(pSI30), undetectable as free-living cells, was found by enrichment as irreversibly bound sessile forms.
(6) Endoscopic resection of large sessile adenomas can be safe and effective.
(7) Pieces of Douglas fir and polyvinyl chloride were colonized in a recirculating system and the comparative efficacy of two biocides (Bronopol and Kathon) against the sessile and planktonic populations was examined.
(8) A 44-year-old woman was found to have a sessile lesion replacing most of her endometrium and endocervical mucosa, consisting of an intimate admixture of endometrial glands, endometrial stroma, and smooth muscle.
(9) Microscopically, they varied from complex papillary to sessile nodular growths.
(10) In the various tested situations in which the migration of cells to lymph nodes was inhibited, it seemed to be the relationship of the cell surfaces of the sessile and circulating cells which played an important role in the outcome of their interactions.
(11) This role includes many facets of immunity such as the effects of antigen specificity, immunologic memory, differential behavior of recirculating or sessile populations, and local and systemic contact between antigen and effector cells.
(12) The mineralization activity of sessile catheter-associated bacteria was unaffected by four hr.
(13) The expression of HLA-DR, HLA-DP and HLA-DQ antigens and of the associated invariant chain (Ii) was studied immunohistologically in sessile cells of normal ileum and ileum affected by Crohn's disease which was taken as a model for chronic inflammation.
(14) Large polyps are sessile or pedunculated lesions that are larger than or equal to 3 cm in size.
(15) Evidence is presented that upon stimulation with endotoxin (lipopolysaccharide, LPS), Kupffer cells, the body's largest pool of sessile macrophages, synthesize and liberate a factor whose immunological, cytotoxic and chemical properties are those described for tumor necrosis factor (TNF)-alpha.
(16) We have devised a modification of the sessile drop method for making the required measurements.
(17) Depending on three related factors (increasing size, a sessile rather than pedunculated mode of growth, and a villous rather than tubular microscopic architecture), one may find minute (1 to 2-mm) or microcancer with increasing frequency in adenomas.
(18) and Dolichoderinae (Tapinoma sessile, Conomyrma insana, Conomyrma wheeleri).
(19) B lymphocyte development occurs in the intersinusoidal spaces of bone marrow in association with a sessile population of stromal cells.
(20) When the results for five strains were studied by analysis of variance at 6 and 24 h, the main variable was the antibiotic concentration, followed by the culture conditions, e.g., planktonic or sessile bacteria, the strain tested, and the time of contact.