Degree Of Site Specificity Research Articles

Strategic environmental assessment methodologies—applications within the energy sector

Strategic Environmental Assessment (SEA) is a procedural tool and within the framework of SEA, several different types of analytical tools can be used in the assessment. Several analytical tools are presented and their relation to SEA is discussed including methods for future studies, Life Cycle Assessment, Risk Assessment, Economic Valuation and Multi-Attribute Approaches. A framework for the integration of some analytical tools in the SEA process is suggested. It is noted that the available analytical tools primarily cover some types of environmental impacts related to emissions of pollutants. Tools covering impacts on ecosystems and landscapes are more limited. The relation between application and choice of analytical tools is discussed. It is suggested that SEAs used to support a choice between different alternatives require more quantitative methods, whereas SEAs used to identify critical aspects and suggest mitigation strategies can suffice with more qualitative methods. The possible and desired degree of site-specificity in the assessment can also influence the choice of methods. It is also suggested that values and world views can be of importance for judging whether different types of tools and results are meaningful and useful. Since values and world views differ between different stakeholders, consultation and understanding are important to ensure credibility and relevance.

The innate and early immune response to pathogen challenge in the female genital tract and the pivotal role of epithelial cells

The female reproductive tract is immunologically unique in its requirement for tolerance to allogeneic sperm and, in the upper tract, to the conceptus. However, it must also be appropriately protected from, and respond to, a diverse array of sexually transmitted pathogens. Some of these infections can be lethal (e.g. Human Immunodeficiency Virus (HIV), Human Papilloma Virus (HPV)), and others (e.g. Chlamydia trachomatis and Neisseria gonorrhoeae) can have potentially devastating reproductive sequelae. Interactions between a host and a pathogen are complex, diverse and regulated, and are a function of the individual pathogen, and host immunity. Although there is undoubtedly commonality in the mucosal immune response, there is also evidence of a degree of site-specificity in immune mechanisms, dependent upon the function and anatomical location of an organ. In this article, we review the evidence on the pivotal role of epithelial cells in the innate and early immune response to pathogen challenge in female genital tract tissues, and examine the evidence that the ‘sterile’ upper and the ‘non-sterile’ lower female genital tract may maintain a different immunological surveillance milieu, and may also respond differentially to pathogen challenge. We also review the unique characteristics, and subsequent ramifications of the acute cervical immune response to C. trachomatis, and discuss how natural antimicrobial mediators of immunity may be utilized to decrease the spread of sexually transmitted infections.

Crop production and water-use. IV. Yield functions for sugarbeet

The water-use model (watyield) was used to estimate a number of variables which were then related to the actual yields recorded in long term sugarbeet experiments carried out at several sites in England over the last 30–40 years. Nine functions were developed which are based on yield/water-input, yield/crop evaporation and (the equivalent of) relative yield/relative crop evaporation relationships. In all cases, highly significant linear correlations were obtained but the levels of precision, and degree of site specificity, varied. For irrigation planning and water allocation, three approaches are recommended with increasing sophistication and, in general, precision. These are (1) relating yield increases to the estimated irrigation need; (2) relating actual yields to crop evaporation totals; and (3) determining actual yields for rainfed and irrigated crops from the calculated seasonal totals of the ‘effective’ solar radiation intercepted by the crop canopy. These values can be estimated with the model using standard weather and soil physical data appropriate to the locality and the crop.

Sites of preferred interaction between double-stranded pBR322 DNA and 7-methylpyrido[3,4-c]psoralen

7-Methylpyrido[3,4-c]psoralen has recently been found to photosensitize the crosslinking and cleavage of double-stranded pBR322 DNA (4361 bp) with an unusual degree of site specificity. Following cleavage of the photosensitized pBR322 with the restriction enzymes Pvu II and BamH I, the main fragments were analyzed electrophoretically. Only three possible cleavage areas on the plasmid were suggested by this analysis. They were within the ranges bounded by the positions 801–926, 3172–3303 and 4226–4310. The sensitizer also induced selective cleavage in the related plasmid pUC19 (2686 bp), but the pattern was somewhat more complicated and was not analyzed in detail.

Methylnaloxonium diffuses out of the rat brain more slowly than naloxone after direct intracerebral injection

The value of intracerebral injections as a means of relating brain structure and function is dependent on the degree of site specificity of the injection. The purpose of this study was to compare the distribution over time of naloxone and its quaternary derivative, methylnaloxonium, after intracerebral microinjection. One microliter of tritiated naloxone (NAL) or methylnaloxonium (MN 10.0 ng, 12.8 nCi for both drugs) was infused directly into the n. raphe pontis. Each animal was then decapitated at a specific time (2.5, 5.0, 15, 30, or 60 min), the brain was removed and dissected into hindbrain, cerebellum, midbrain and cortex. Tritium beta emissions of brain homogenates were measured 1 day later. MN remained better localized to the injection site than did the same volume of the more lipophilic NAL. Within 15 minutes, less than 5% of the NAL remained in the hindbrain compared with nearly 40% of the MN. These results suggest that MN may be a better probe than NAL for investigating the relationship of opioid receptor anatomy and function, particularly for dependent variables requiring sustained time courses.

Patterns of histone acetylation

The N-terminal domains of all four core histones are subject to reversible acetylation at certain lysine residues. This modification has been functionally linked to transcription, histone deposition at replication and to histone removal during spermatogenesis. To increase understanding of the significance of this modification we have studied the specificity of site utilisation in the monoacetyl, diacetyl and triacetyl forms of histones H3, H4 and H2B (histone H2A has only a single modification site), using pig thymus and HeLa cells as the source of histones. The HeLa histones were extracted from cells grown both with and without butyrate treatment. It is found that for histone H3 there is a fairly strict order of site occupancy: Lys14, followed by Lys23, followed by Lys18 in both pig and HeLa histones. Since the order and specificity is the same when butyrate is added to the HeLa cell cultures, we conclude that addition of the fatty acid does not scramble the specificity of site utilisation, but merely allows more of the natural forms of modified histone to accumulate. For histone H4, the monoacetyl form is exclusively modified at Lys16, but further addition of acetyl groups is less specific and progresses through sites 12, 8 and 5 in an N-terminal direction. Similar results were obtained for H4 from both pig thymus and butyrate-treated HeLa cells. Histone H2B could be studied in detail only from butyrate-treated HeLa cells and a much lower level of site specificity was found: sites 12 and 15 were preferred to the more N- and C-terminal sites at Lys5 and Lys20. The data reinforces the view that lysine acetylation in core histones is a very specific phenomenon that plays several functionally distinct roles. The high degree of site specificity makes it unlikely that the structural effects of acetylation are mediated merely by a generalised reduction of charge in the histone N-terminal domains.

λp lac10 Transducing bacteriophage: DNA primary structure of the region of the abnormal excision

In studying molecular mechanisms of the formation of transducing bacteriophages, we have elucidated the primary structure of the phage-bacterial DNA junction which resulted from the abnormal excision of the λp lac10 phage. The process is structurally similar to the excision of the λp lac5 phage and involves, in both cases, highly homological DNA stretches approximately 20 bp long, one of them being a part of the Z-Y spacer of the lac operon and possessing a developed secondary structure. The conception of regioselective recombination as a type of illegitimate recombinational process with a certain degree of site-specificity is suggested.

Site-specific drug delivery to CNS: Old and new

Delivery of drugs to specific sites in the CNS represents an essential therapeutic challenge. Extradural administration of opiates successfully delivers drugs to the CNS. The levodopa-carbidopa combination achieved some degree of site-specific delivery by pharmacological methods. Antibiotics have been administered through cannula directly into ventricles. Invasive methods offer the greatest degree of site-specificity.

Peptidergic control of male rat sexual behavior: The effects of intracerebral injections of substance P and cholecystokinin

Behavioral experiments examined the roles of substance P (SP) and cholecystokinin (CCK) in male rat copulatory behavior. Male copulatory behavior was recorded subsequent to injections of different doses of CCK and SP into the medial preoptic-anterior-hypothalamic area (MPOA-AH), caudate/putamen (CP), or the lateral ventricles (LV) in sexually experienced male rats. In the first experiment, three different doses of SP (10, 100, and 200 ng/cannula) injected bilaterally into the MPOA-AH produced marked changes in several components of male copulatory behavior. Latencies were most affected. All three doses significantly shortened the interval to initiate copulation, and the 10 and 100 ng, but not 200 ng dose also significantly reduced ejaculation latencies. Injections of 10 ng of SP into the CP did not affect sexual behavior, while injections into the LV produced changes different from those of MPOA-AH injections. These data argue for some degree of site specificity of the effects of the MPOA-AH injections. Bilateral injections of 10 ng of SP into the MPOA-AH, were incapable of inducing copulatory behavior in castrated rats deprived of testosterone. Injections of an undiluted SP antiserum (2 μl/cannula) into the MPOA-AH produced a dramatic impairment of male copulatory behavior. These injections significantly lengthened mount, intromission, and ejaculation latencies, while having no effect on the number of mounts or intromissions prior to ejaculation. In contrast, bilateral injections of CCK-8 (10, 100, and 200 ng/cannula) into the MPOA-AH failed to affect any parameter of male copulatory behavior. The results of the present study provide the first support for a role of SP in the neural regulation of male rat sexual behavior and suggest that a SP-sexually dimorphic pathway forms part of the neural circuitry important for the expression of male rat sexual behavior.

HAUL‐OUT PATTERNS, SITE FIDELITY AND ACTIVITY BUDGETS OF MALE HOOKER'S SEA LIONS (PHOCARCTOS HOOKERI) ON THE NEW ZEALAND MAINLAND

AbstractDiurnal and seasonal haul‐out patterns, site fidelity and activity budgets of individually identified Hooker's sea lions were studied for two years at Papanui Beach, Otago Peninsula, New Zealand.Fourteen male sea lions were identified. Lengths ranged from 1.65 m–2.28 m and estimated ages from 2‐11 yr. The population consisted of four sexually and socially mature (potentially breeding), eight sexually mature but socially immature and two immature males. Most haul‐outs (95.6%) were by nine identifiable individuals (Residents) returning on a regular basis, suggesting a high degree of site specificity. Emigration and recruitment were low in relation to the length of the study. Daily arrivals (mean = 0844 h, SD = 1.49) and departures (mean = 1802 h, SD = 1.18) indicate nocturnal feeding. During March 1986 sea lions spent 43.8% of each day ashore (= 78% of daylight hours). Numbers of sea lions hauled out declined in both breeding seasons; in 1986/87 this was due to a decrease in haul‐out frequency of resident animals. All but one of these sea lions returned after the breeding season.Sea lions preferentially selected the middle and the extreme ends of the beach as haul‐out sites. During winter use was made of the grass dunes as haul‐out areas.There were significant differences in the frequencies of behavioral activities between summer and winter; more time was allocated to resting in summer.

Tissue-specific N-glycosylation, site-specific oligosaccharide patterns and lentil lectin recognition of rat Thy-1.

To examine the extent to which protein structure and tissue-type influence glycosylation, we have determined the oligosaccharide structures at each of the three glycosylation sites (Asn-23, 74 and 98) of the cell surface glycoprotein Thy-1 isolated from rat brain and thymus. The results show that there is tissue-specificity of glycosylation and that superimposed on this is a significant degree of site-specificity. On the basis of the site distribution of oligosaccharides, we find that no Thy-1 molecules are in common between the two tissues despite the amino acid sequences being identical. We suggest, therefore, that by controlling N-glycosylation a tissue creates an unique set of glycoforms (same polypeptide but with oligosaccharides that differ either in sequence or disposition). The structures at each of the three sites were also determined for the thymocyte Thy-1 that binds to lentil lectin (Thy-1 L+) and for that which does not (Thy-1 L-). Segregation of intact thymus Thy-1 into two distinct sets of glycoforms by lentil lectin was found to be due to the structures at site 74. Analysis of oligosaccharide structures at the 'passenger' sites (23 and 98) suggests that either Thy-1 L+ and Thy-1 L- molecules are made in different cell-types or that the biosynthesis of oligosaccharides at one site is influenced by the glycosylation at other sites.

Ca lectin gene insertion has the structural features of a transposable element

The single gene Le1, coding for soybean seed lectin, was compared to le1, a naturally occurring mutant allele containing a 3.4 kb insertion within its coding region. Le1 is devoid of introns and produces a 1.0 kb mRNA. It codes for a signal sequence of 32 amino acids and a mature protein of 253 amino acids. With the exception of six single-base substitutions, the coding and flanking sequences in le1 are identical with those in the uninterrupted gene. The insertion termini are imperfect inverted repeats flanked by a 3 bp duplication of lectin target DNA. Inverted repeats within the lectin gene are located symmetrically with respect to the insertion site and are homologous to a region of the insertion termini. These molecular traits conform with the structural aspects of transposable elements in other organisms and imply some degree of site specificity.

Individual Recognition, Intragroup Cohesion and Intergroup Spacing: Evidence From Sound Playback To Forest Monkeys

AbstractThe contexts and functions of several loud mangabey vocalizations, particularly the "whoopgobble", were investigated observationally and experimentally. Whoopgobbles are notable for their audibility and distinctiveness over long distances, their temporal pattern of delivery, and particularly their stereotypy and individual distinctiveness. On the other hand, contexts of and responses to these vocalizations are variable and sometimes nonobvious. In order to control context and more systematically investigate response, an experimental method involving playback of recorded vocalizations was developed. Although precautions against habituation were necessary, mangabey responses to playbacks were clearcut and repeatable. Answering vocalizations, changes in group movement, and changes in the dispersion of individuals within a group occurred only in response to mangabey vocalizations. Whoopgobble playbacks provoked a pattern of response, including most notably the rapid approach of one adult male (the "RA" male) from each group, which was specific to this call. Playback of whoopgobbles between 100 and 600m from mangabey groups indicated that this call does transmit information regarding the identity of the vocalizing individual and group over these distances. Test groups moved away from neighboring- and unknown-group calls, but towards those of their own males - particularly those of RA males. RA males, on the other hand, do not approach calls of other males from their own groups. Within a group, whoopgobbles may thus increase cohesion and influence the direction of movements. Characteristics of whoopgobble form and context are discussed with regard to hypothesized functions of these and other forest monkey loud calls. Responses by free-ranging mangabeys to playback of the whoopgobble confirm its role in maintaining distance between groups. Response was found to be independent of group size, despite the fact that whoopgobble rate is closely related to this variable and thus could transmit such information. Since responses were also found to be independent of location within the home range, intergroup spacing among mangabeys appears not be be "territorial", site defense does not occur. Nevertheless, the central areas in at least some mangabey groups' home ranges were never penetrated by neighbors. Playback tests with black-and-white colobus and blue monkeys, among which territorial spacing has been reported, indicate that responses to loud calls have some degree of site-specificity among these species. But the mangabey pattern of intergroup spacing appears to result from a combination of low group density, site attachment within groups, and site-independent avoidance between groups. These results emphasize that spacing "system" and "pattern" are not necessarily equivalent; a given set of spacing behaviors can result in different spacing patterns under different ecological conditions, while a given pattern may be obtained by any of several behavioral means. Evidence for site-independent spacing in other primate species is discussed.

Reversion of acridine mustard-induced ad-3 mutants of Neurospora crassa

Previous analysis of adenine-3 ( ad-3) mutants of Neurospora crassa induced by the acridine mustard, 2-methoxy-6-chloro-9-[3-(ethyl-2-chloroethyl)aminopropylaamino]-acridine · 2HCl (ICR-170), suggested a number of possible mutagenic events for this compound including: ( I) extended intragenic alterations covering more than one site, such as deletions; (2) base-pair substitutions (transitions or transversions) with a high degree of site specificity; and (3) additions and/or deletions of one or more base pairs (frameshift mutations). The revertibility of ICR-170-induced ad-3 mutants has been studied with ICR-170 and nitrous acid. A majority ( 16 24 ) of the ICR-170-induced mutants were clearly reverted by ICR-170, while none of the mutants were clearly reverted by nitrous acid. Genetic analysis of the ICR-170-induced revertants did not provide evidence for suppressor mutation. The ICR-170-induced revertants had the same growth rate as ad-3 + strains. Each of the ICR-170 components (acridine and nitrogen mustard) tested separately did not revert an ICR-170-revertible strain. The data indicate that the mutagenic events induced by ICR-170 at the ad-3 region of N. crassa are predominantly single-site, nontransitional alterations, probably of the frameshift type.