Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving viable micro-organism
Reexamination Certificate
2000-04-06
2002-08-20
Leary, Louise N. (Department: 1627)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving viable micro-organism
C435S025000, C435S004000, C435S254100, C435S968000
Reexamination Certificate
active
06436660
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to screening methods involving use of metabolic oxidation-reduction indicator dyes for identifying antimicrobial agents.
BACKGROUND OF THE INVENTION
Infectious diseases can be caused by a number of organisms, including bacteria, fungi, protozoans and other parasites, and viruses. Bacteria as a group generally include gram-negative bacteria, gram-positive bacteria, spirochetes, rickettsiae, mycoplasmas, mycobacteria and actinomycetes. Resistance of bacteria and other pathogenic organisms to antimicrobial agents is an increasingly troublesome problem. The accelerating development of antibiotic-resistant bacteria, intensified by the widespread use of antibiotics in farm animals and overprescription of antibiotics by physicians, has been accompanied by declining research into new antibiotics with different modes of action. [
Science,
264: 360-374 (1994).]
Antibacterial agents can be broadly classified based on chemical structure and proposed mechanism of action, and major groups include the following: (1) the &bgr;-lactams, including the penicillins, cephalosporins and monobactams; (2) the aminoglycosides, e.g., gentamicin, tobramycin, netilmycin, and amikacin; (3) the tetracyclines; (4) the sulfonamides and trimethoprim; (5) the fluoroquinolones, e.g., ciprofloxacin, norfloxacin, and ofloxacin; (6) vancomycin; (7) the macrolides, which include for example, erythromycin, azithromycin, and clarithromycin; and (8) other antibiotics, e.g., the polymyxins, chloramphenicol and the lincosamides.
Antibiotics accomplish their anti-bacterial effect through several mechanisms of action which can be generally grouped as follows: (1) agents acting on the bacterial cell wall such as bacitracin, the cephalosporins, cycloserine, fosfomycin, the penicillins, ristocetin, and vancomycin; (2) agents affecting the cell membrane or exerting a detergent effect, such as colistin, novobiocin and polymyxins; (3 ) agents affecting cellular mechanisms of replication, information transfer, and protein synthesis by their effects on ribosomes, e.g., the aminoglycosides, the tetracyclines, chloramphenicol, clindamycin, cycloheximide, fucidin, lincomycin, puromycin, rifampicin, other streptomycins, and the macrolide antibiotics such as erythromycin and oleandomycin; (4) agents affecting nucleic acid metabolism, e.g., the fluoroquinolones, actinomycin, ethambutol, 5-fluorocytosine, griseofulvin, rifamycins; and (5) drugs affecting intermediary metabolism, such as the sulfonamides, trimethoprim, and the tuberculostatic agents isoniazid and para-aminosalicylic acid. Some agents may have more than one primary mechanism of action, especially at high concentrations. In addition, secondary changes in the structure or metabolism of the bacterial cell often occur after the primary effect of the antimicrobial drug.
Protozoa account for a major proportion of infectious diseases worldwide, but most protozoan infections occur in developing countries. Treatment of protozoan infections is hampered by a lack of effective chemotherapeutic agents, excessive toxicity of the available agents, and developing resistance to these agents.
Fungi are not only important human and animal pathogens, but they are also among the most common causes of plant disease. Fungal infections (mycoses) are becoming a major concern for a number of reasons, including the limited number of antifungal agents available, the increasing incidence of species resistant to known antifungal agents, and the growing population of immunocompromised patients at risk for opportunistic fungal infections, such as organ transplant patients, cancer patients undergoing chemotherapy, burn patients, AIDS patients, or patients with diabetic ketoacidosis. The incidence of systemic fungal infections increased 600% in teaching hospitals and 220% in non-teaching hospitals during the 1980's. The most common clinical isolate isolated is
Candida albicans
(comprising about 19% of all isolates). In one study, nearly 40of all deaths from hospital-acquired infections were due to fungi. [Sternberg,
Science,
266:1632-1634 (1994).].
Known antifungal agents include polyene derivatives, such as amphotericin B (including lipid or liposomal formulations thereof) and the structurally related compounds nystatin and pimaricin; flucytosile (5-fluorocytosine); azole derivatives (including ketoconazole, clotrimazole, miconazole, econazole, butoconazole, oxiconazole, sulconazole, tioconazole, terconazole, fluconazole, itraconazole, voriconazole [Pfizer], poscaconazole [SCH56592, Schering-Plough]) and ravuconazole; allylamines-thiocarbamates (including tolnaftate, naftifine and terbinafine); griseofulvin; ciclopirox; haloprogin; echinocandins (including caspofungin [MK-0991, Merck], FK463 [Fujisawa] and VER-002 [Versicor]); nikkomycins; and sordarins. Recently discovered as antifungal agents are a class of products related to bactericidal permneability-increasing protein (BPI), described in U.S. Pat. Nos. 5,627,153, 5,858,974, 5,652,332, 5,856,438, 5,763,567 and 5,733,872, the disclosures of all of which are incorporated herein by reference.
Bactericidal/permeability-increasing protein (BPI) is a protein isolated from the granules of mammalian polymorphonuclear leukocytes (PMNs or neutrophils), which are blood cells essential in the defense against invading microorganisms. See Elsbach, 1979,
J. Biol. Chem.,
254: 11000; Weiss et al., 1987,
Blood
69: 652; Gray et al., 1989,
J Biol. Chem.
264: 9505. The amino acid sequence of the entire human BPI protein and the nucleic acid sequence of DNA encoding the protein (SEQ ID NOS: 1 and 2) have been reported in U.S. Pat. No. 5,198,541 and
FIG. 1
of Gray et al.,
J. Biol. Chem.,
264:9505 (1989), incorporated herein by reference. Recombinant human BPI holoprotein has also been produced in which valine at position 151 is specified by GTG rather than GTC, residue 185 is glutamic acid (specified by GAG) rather than lysine (specified by AAG) and residue 417 is alanine (specified by GCT) rather than valine (specified by GTT). An N-terminal fragment of human BPI possesses the anti-bacterial efficacy of the naturally-derived 55 kD human BPI holoprotein. (Ooi et al., 1987, .
J. Bio. Chem.
262: 14891-14894). In contrast to the N-terminal portion, the C-terminal region of the isolated human BPI protein displays only slightly detectable anti-bacterial activity against gram-negative organisms and some endotoxin neutralizing activity. (Ooi et al., 1991,
J. Exp. Med.
174: 649). An N-terminal BPI fragment of approximately 23 kD, referred to as rBPI
23
, has been produced by recombinant means and also retains anti-bacterial, including anti-endotoxin activity against gram-negative organisms (Gazzano-Santoro et al., 1992,
Infect. Immun.
60: 4754-4761). An N-terminal analog designated rBPI
21
(also referred to as rBPI(1- 193)ala
132
) has been described in U.S. Pat. No. 5,420,019.
Three separate functional domains within the recombinant 23 kD N-terminal BPI sequence have been discovered (Little et al., 1994,
J. Biol. Chem.
269: 1865). These functional domains of BPI designate regions of the amino acid sequence of BPI that contributes to the total biological activity of the protein and were essentially defined by the activities of proteolytic cleavage fragments, overlapping 15-mer peptides and other synthetic peptides. Domain I is defined as the amino acid sequence of BPI comprising from about amino acid 17 to about amino acid 45. Initial peptides based on this domain were moderately active in both the inhibition of LPS-induced LAL activity and in heparin binding assays, and did not exhibit significant bactericidal activity. Domain II is defined as the amino acid sequence of BPI comprising from about amino acid 65 to about amino acid 99. Initial peptides based on this domain exhibited high LPS and heparin binding capacity and exhibited significant antibacterial activity. Domain III is defined as the amino acid sequence of BPI compri
Leary Louise N.
Marshall Gerstein & Borun
XOMA Technology Ltd.
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