Antibacterial activity of short hydrophobic and basic-rich peptides

OBJECTIVE-To design short and potent analogs of bovine lactoferricin by use of the concepts of lipophilic bulk and cationic charge. SAMPLE POPULATION-5 synthetic peptides of bovine lactoferricin. PROCEDURE: Antibacterial peptides were constructed by synthesizing several decapeptides rich in arginine and tryptophan. Basic residues of bovine lactoferricin (bLf 20-29; residues 20 to 29) were modified by substitution with arginine or lysine and nonbasic residues were modified by substitution with tryptophan, phenylalanine, or isoleucine. Synthetic peptides of bovine lactoferrin (LFB) were designated as LFB-RW (RRWWWRWRRW), LFB-KW (KKWWWKWKKW), LFB-RWa (RRWWRRWRRW), LFB-RF (RRFFFRFRRF), and LFB-RI (RRIIIRWRRI), where R, K, W, F, and I stand for arginine, lysine, tryptophan, phenylalanine, and isoleucine, respectively. Peptides were evaluated by determining their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. RESULTS: LFB-RW, LFB-KW, and LFB-RWa possessed equivalent potency as bLf 20-29 against E coli. LFB-RW and LFB-RWa had a 2-fold increase in growth-inhibitory and bactericidal activity against S aureus, compared with bLf 20-29. LFB-RI had the lowest MIC value against E coli among the peptides but lost bactericidal activity. LFB-RW and LFB-KW had stronger bactericidal activities against S aureus or E faecalis, respectively, as well as E coli than the other synthetic peptides. LFB-RF also had antibacterial activity, but this was 2-fold less than that of LFB-RW, as determined by MIC and MBC values. CONCLUSIONS AND CLINICAL RELEVANCE: In construction of potent antibacterial peptides, inclusion of arginine, lysine, tryptophan, or isoleucine residues enhances effectiveness against certain bacteria, as measured by MIC or MBC values.     

Raising livestock in resource-poor communities of the North West Province of South Africa--a participatory rural appraisal study

A participatory research model was used in six village communities in the Central Region of the North West Province of South Africa in order to achieve the following broad objectives: to obtain information on the challenges owners face in raising livestock in these areas and to evaluate the livestock owners' level of knowledge of internal parasites in their animals. Information obtained at participatory workshops clearly indicated a need for improvements in water supply, schools, job creation, and health services. Lack of pasture for grazing livestock was also cited as being important. Other most frequently mentioned livestock problems included 'gall sickness' (a vaguely defined condition not necessarily referring to anaplasmosis), parasites (both external and internal), chicken diseases and ingestion of plastic bags discarded in the environment. When livestock owners were questioned during individual interviews, most were able to identify the presence of parasites in either the live or dead animal. However, it seems likely that this is limited to the identification of tapeworms. It was found that most livestock owners use a combination of treatments, ranging from traditional to folklore to commercial. There were some difficulties in using the participatory methods since it was the first time that the facilitators and the communities had been exposed to them. Many communities had difficulty in dealing with the concept of finding solutions within the community, which is such an integral part of participatory methods.     

Comparison of Soil Receptivity to Thielaviopsis basicola, Aphanomyces euteiches, and Fusarium solani f. sp. pisi Causing Root Rot in Pea

ABSTRACT Soil receptivity as a quantifiable characteristic ranging from conduciveness to suppressiveness to soilborne pea pathogens Thielaviopsis basicola and Aphanomyces euteiches was determined by analysis of differences in disease response curves obtained by artificial introduction of inoculum into natural field soil samples. Several parameters, including maximum root rot severity, the area under the health index curve, scores on the first axis of a principal component analysis (PCA) on dose responses, and Weibull model fitting were used to describe the disease responses. In all cases, the Weibull model gave satisfactory fits. PCA yielded a first axis that comprised 86% of the variance found when using Weibull predicted responses for T. basicola and 74% of the variance found for A. euteiches. This PCA axis essentially represented the average increase in disease severity due to the addition of increasing doses of inoculum to the soil. The Weibull scale parameter B, which represents the amount of inoculum necessary to increase root rot severity by 63% with respect to the level caused by pathogens naturally present in the soil, is another means of quantifying the receptivity of soils to these plant pathogens. Weibull parameter B, maximum root rot severity, the areaunder the health index curve, and the scores on the first PCA axis were strongly correlated for each of the pathogens tested individually. To compare the extent and behavior of soil receptivity responses to different pathogens, Weibull parameters B and C (slope at dose B) were chosen because of their universal definition, in contrast to PCA scores. Comparison of the average levels of Weibull parameters B and C indicated significant differences between the pathogens. Yet, no significant similarity in the ranking of the soils was found for the three pathogens, demonstrating that individual soils may interact with different pathogens in totally different ways. In general, soils were suppressive to T. basicola but conducive to A. euteiches, whereas their response to Fusarium solani f. sp. pisi ranged from conducive to suppressive. Therefore, risk assessment of soils prior to planting may require different strategies for each pathogen. Bioassays with soil samples taken before the last pea crop in 1987 and 1991 revealed a significant increase in the natural inoculum potential of soils that mainly was accounted for by A. euteiches and Pythium spp. These results strongly indicate that A. euteiches must be considered one of the most threatening pathogens to pea crops in the Netherlands.     

A SHORT METHOD FOR THE PREPARATION OF ANIMAL TISSUES FOR STAINING

Increase of the blood sugar which invariably follows administration of cortico-adrenal extract to adrenalectomized cats with symptoms of insufficiency is a reliable index of potency and affords a means of bio-assay of the material.     

Near-synchronous interhemispheric termination of the last glacial maximum in mid-latitudes

Isotopic records from polar ice cores imply globally asynchronous warming at the end of the last glaciation. However, 10Be exposure dates show that large-scale retreat of mid-latitude Last Glacial Maximum glaciers commenced at about the same time in both hemispheres. The timing of retreat is consistent with the onset of temperature and atmospheric CO2 increases in Antarctic ice cores. We suggest that a global trend of rising summer temperatures at the end of the Last Glacial Maximum was obscured in North Atlantic regions by hypercold winters associated with unusually extensive winter sea ice.     

Amplification of surface temperature trends and variability in the tropical atmosphere

The month-to-month variability of tropical temperatures is larger in the troposphere than at Earth's surface. This amplification behavior is similar in a range of observations and climate model simulations and is consistent with basic theory. On multidecadal time scales, tropospheric amplification of surface warming is a robust feature of model simulations, but it occurs in only one observational data set. Other observations show weak, or even negative, amplification. These results suggest either that different physical mechanisms control amplification processes on monthly and decadal time scales, and models fail to capture such behavior; or (more plausibly) that residual errors in several observational data sets used here affect their representation of long-term trends.     

Andrastins A-D, Penicillium roqueforti Metabolites consistently produced in blue-mold-ripened cheese

This is the first finding of andrastins in blue cheese as well as any other sample type. Here, they were produced by the secondary starter culture Penicillium roqueforti. After purification by normal-phase chromatography followed by combined reverse-phase ion-exchange chromatography, the andrastins A-D were detected by liquid chromatography combined with UV and high-resolution mass spectrometry. In 23 representative samples of European blue cheeses, andrastin A was consistently found in quantities between 0.1 and 3.7 microg/g of cheese (median 2.4 microg/g). Assuming the same molar response factors as for andrastin A, the B, C, and D analogues were present in approximately 5-, 3-, and 5-20-fold lower amounts than andrastin A, respectively. The andrastins are protein farnesyltransferase inhibitors and are capable of inhibiting the efflux of anticancer drugs from multidrug-resistant cancer cells. Thus, their presence in common blue cheese suggests a potential for a positive or negative impact on human health.