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Biomedical subjects

J M Wells

Publications and source records attributed to J M Wells.

At least 91 records · Page 5Linked to original sources
PubMed1981

Medium for isolation and growth of bacteria associated with plum leaf scald and phony peach diseases.

Rickettsia-like bacteria associated with plum leaf scald and phony peach diseases were isolated from diseased but not from healthy tissues and cultured on charcoal-yeast extract medium (BCYE) buffered with ACES (2-[(2-amino-2-oxoethyl) amino]-ethanesulfonic acid). Optimum conditions for isolation and growth on BCYE medium were pH 6.5 to 6.9 at 20 and 25 degrees C under normal atmosphere. Growth of primary colonies and first-passage subcultures was restricted, and colonies reached a maximum diameter of 0.6 mm in 60 days. After 12 passages, subcultures reached maximum growth in 21 days. The rickettsia-like bacteria from BCYE cultures were gram negative, serologically the same as those present in diseased peach and plum, and composed of rod-shaped cells measuring 0.35 by 5 mum (average diameter and maximum length) in a matrix of filamentous strands of similar width but of variable length.

Journal Article↗
PubMed1981

Isolation of Citreoviridin from Penicillium charlesii Cultures and Molded Pecan Fragments.

The extraction and systematic fractionation of Penicillium charlesii Smith cultures and contaminated pecan fragments yielded the yellow mycotoxin citreoviridin. Citreoviridin proved acutely toxic to 1-day-old chickens, with an oral 50% lethal dose of 37.5 mg/kg, and showed plant growth inhibition in wheat coleoptiles even at concentrations as low as 10 M. It was toxic to corn seedlings but did not affect young tobacco seedlings.

Journal Article↗
PubMed1976

Toxigenic species of Penicillium, Fusarium, and Aspergillus from weevil-damaged pecans.

Of a total of 2392 fungi isolated from weevil-damaged pecans, 46.4% were Alternaria and Epicoccum, 23.9% were Penicillium, 12.4% were Pestalotia and Monochaeta, 6.5% were Cladosporium, 6.4% were Fusarium, and less than 2% each were Phoma, Aspergillus, Rhizopus, Trichothecium, and miscellaneous. Chloroform extracts of 34 of 105 representative Penicillium isolates, 3 of 28 Fusarium isolates, and 3 of 23 Aspergillus isolates were toxic to day-old cockerels during three bioassays. Eight of the toxic extracts from Penicillium spp. were tremorgenic. One tremorgenic isolate was identified as P. paxilli, four were identified as P. lanoso-coeruleum, and three as P. cyclopium. Nine of the non-tremorgenic isolates were identified as P. citrinum, five as P. aurantio-virens, three as P. oxalicum, and two as P. meleagrinum. Others were identified as one each of P. brevi-compactum (Series), P. nigricans (Series), P. roqueforti, P. rugulosum (Series), P. terrestre, and P. stoloniferium. One was unidentified. Toxigenic Aspergillus isolates were all A. flavus. Two of the toxic Fusarium isolates were F. moniliforme, and one was unidentified.

Animals↗
PubMed1976

Toxicity and plant growth regulator effects of cytochalasin H isolated from Phomopsis sp.

A biologically active metabolite was found in crude extracts of an unidentified species of Phomopsis isolated from weevil-damaged pecans. Purified metabolite was toxic to day-old cockerels, with an LD50 of 12.5 mg/kg, and was markedly inhibitory to growth the floral development of tobacco plants at concentrations of 10(-2) to 10(-4) M. IR and 1H-nmr spectra indicated an alkylpheny moiety with a single nitrogen atom present as a secondary amide; and acetate ester, OH, CH3, and a trans-double bond function. Elemental and high-resolution mass-spectral analysis indicated a formula of C30H39NO5 and a molecular weight of 493.2886. The metabolite was identified as cytochalasin H.

Animals↗
PubMed1976

Coral-algal associations: capacity for producing and sustaining elevated oxygen tensions in situ.

Net oxygen production during photosynthesis by all plants requires adaptation to intracellular O2 tensions in excess of 0.21 ATA. The symbiotic association of zooxanthellae (algae) in the tissues of many actinozoans and hydrozoans (corals and anemones) suggests such an adaptation in these tissues as well, and raises the question as to degree. Oxygen production by zooxanthellae in a single coral head of Montastrea cavernosum was monitored daily in situ in a closed, recirculating 15-liter system. The net photosynthetic activity repeatedly raised the PO2 to more than 0.5 ATA, indicating that even higher tensions existed in the coral's tissues in order to cause this increase and suggesting that coral tissue may represent another example of an oxygen-adapted tissue.

Adaptation, Biological↗
PubMed1975

Emodin, a toxic metabolite of Aspergillus wentii isolated from weevil-damaged chestnuts.

A diarrheagenic toxin from culture extracts of Aspergillus wentii Wehmer isolated from weevil-damaged Chinese chestnuts was identified as emodin (2-methyl-4,5,7-trihydroxyanthraquinone). The orange-red, crystalline toxin (mp 255 to 257 C) showed ultraviolet absorption maxima in ethyl alcohol at 223, 250, 267, 290, and 442 nm, and infrared absorption maxima at 3,400 cm-1 (OH), 1,635, and 1,625 CM-1. Chemical shifts and coupling constants of the proton magnetic resonance spectra of the A. wentii toxin and of authentic emodin agreed. Mean lethal dose of emodin orally administered to 1-day-old DeKalb cockerels was 3.7 mg/kg.

Animals↗
PubMed1975

Toxigenic Aspergillus and Penicillium isolates from weevil-damaged chestnuts.

Aspergillus and Penicillium were among the most common genera of fungi isolated on malt-salt agar from weevil-damaged Chinese chestnut kernels (16.8 and 40.7% occurrence, respectively). Chloroform extracts of 21 of 50 Aspergillus isolates and 18 of 50 representative Penicillium isolates, grown for 4 weeks at 21.1 C on artificial medium, were toxic to day-old cockerels. Tweleve of the toxic Aspergillus isolates were identified as A. wentii, eight as A. flavus, and one as A. flavus var. columnaris. Nine of the toxic Penicillium isolates were identified as P. terrestre, three as P. steckii, two each as P. citrinum and P. funiculosum, and one each as P. herquei (Series) and P. roqueforti (Series). Acute diarrhea was associated with the toxicity of A. wentii and muscular tremors with the toxicity of P. terrestre, one isolate of P. steckii, and one of P. funiculosum.

Animals↗
PubMedDate not supplied

Activated Alzheimer disease platelets retain more beta amyloid precursor protein.

Upon activation, platelet alpha-granules' soluble contents are secreted and membrane-bound contents are translocated to the plasma membrane. Membrane-bound proteins include the beta-amyloid precursor protein (APP) from which the beta-amyloid (A beta) deposits found surrounding the cerebrovasculature of patients with Alzheimer's Disease (AD) may originate. We show here that activated platelets from AD patients exhibit less APP processing, retain more of the protein on their surface, and secrete less as soluble fragments than do controls. Surface labeling demonstrated that there is little APP or CD62 on the surface of resting platelets. Upon activation, control platelets exhibited more of both proteins on their surface, while advanced AD patients exhibited similar amounts of CD62 as controls, but retained significantly more surface APP. AD platelets secreted similar amounts of most soluble alpha-granule contents as controls, but less APP fragments. Together these results suggest a processing defect that may account for greater deposition of A beta-containing products in the vasculature to which activated platelets adhere.

Adult↗
PubMedDate not supplied

Moderate and advanced Alzheimer's patients exhibit platelet activation differences.

We previously reported that platelets from advanced sporadic Alzheimer's disease (AD) patients exhibit two defects: first, an aberrant signal transduction presenting as a thrombin-induced hyperacidification, which is more severe for donors with the apolipoprotein E4 allele (apoE4), and second, an AD-specific Amyloid Precursor Protein (APP) processing defect that presents as retention of APP on the activated platelets' surface and in independent of the apo E allele. This retention of membrane APP correlates with decreased release of soluble APP. To determine at what stage in the disease progression these defects appear, we performed signal transduction and secretion studies on moderate AD patients. Thrombin-activated platelets from these patients do not exhibit either hyperacidification or APP retention; their APP processing and secretion are normal by Western blotting, suggesting that the two platelet defects appear in the advanced stages of AD.

Adult↗
PubMedDate not supplied

Protection against tetanus toxin in mice nasally immunized with recombinant Lactococcus lactis expressing tetanus toxin fragment C.

Mice inoculated intranasally (i.n.) with a recombinant strain of live Lactococcus lactis expressing tetanus toxin fragment C (TTFC), produced both serum and secretory antibodies to TTFC. Killed bacteria which had accumulated TTFC intracellularly in vitro also elicited protective serum antibody responses. There was no requirement for either colonization or invasion of the mucosa. In addition secretory antibody responses in the lung and nasal tissues were elicited after i.n. inoculation in the presence of an adjuvant.

Administration, Intranasal↗