Ethnomedicinal uses of plants for various diseases in the remote areas of Changa Manga Forest, Pakistan / Usos etnomedicinais de plantas para várias doenças nas áreas remotas da Floresta Changa Manga, Paquistão

This study aims at reporting the indigenous knowledge of the medicinal flora from the inhabitants of surroundings of the World's largest artificial planted forest "Changa Manga", Pakistan. Data were collected by direct interviews and group meetings from 81 inhabitants including 32 local healers having information regarding the use of indigenous medicinal plants over a period of one year. Different statistical tools were applied to analyze the data including Frequency citation (FC), Relative frequency citation (RFC), Use Value, Factor of informants consensus and fidelity level. This study reported 73 plant species belonging to 37 plant families and 46 genera. The majority of plant species belong to compositae family. The most commonly used medicinal plants were P. hysterophorus L., P. dactylifera L., S. indicum L, P. harmala L., P. emblica L., and A. indica A.Juss. The greatest number of species was used to cure gastrointestinal disorders. The highest fidelity level (68.18%) was of E. helioscopia to cure gastrointestinal disorders. Maximum fresh uses (17) were reported by C. dactylon (L.) Pars. While the highest number of species reporting fresh uses in similar number was 13. In this study, five novel plants are being reported for the first time in Pakistan for their ethnomedicinal worth. Our data reflect unique usage of the medicinal plants in the study area. The statistical tools used in the study proved useful in pointing the most important and disease category specific plants. High use value plant and the new reported medicinal plants might prove an important source of the isolation of pharmacologically active compounds.

Este estudo tem como objetivo relatar o conhecimento indígena sobre a flora medicinal dos habitantes do entorno da maior floresta artificial plantada do mundo, a Changa Manga, no Paquistão. Os dados foram coletados por meio de entrevistas diretas e reuniões em grupo de 81 habitantes, incluindo 32 curandeiros locais, com informações sobre o uso de plantas medicinais indígenas durante o período de um ano. Diferentes ferramentas estatísticas foram aplicadas para analisar os dados, incluindo citação de frequência (FC), citação de frequência relativa (RFC), valor de uso, fator de consenso dos informantes e nível de fidelidade. Este estudo relatou 73 espécies de plantas pertencentes a 37 famílias de plantas e 46 gêneros. A maioria das espécies de plantas pertence à família Compositae. As plantas medicinais mais utilizadas foram P. hysterophorus L., P. dactylifera L., S. indicum L., P. harmala L., P. emblica L. e A. indica A. Juss. O maior número de espécies foi usado para curar distúrbios gastrointestinais. O maior nível de fidelidade (68,18%) foi de E. helioscopia para cura de distúrbios gastrointestinais. Os usos máximos em fresco (17) foram relatados por C. dactylon (L.) Pars. enquanto o maior número de espécies relatando usos frescos em número semelhante foi de 13. Neste estudo, cinco novas plantas estão sendo relatadas pela primeira vez no Paquistão por seu valor etnomedicinal. Nossos dados refletem o uso exclusivo das plantas medicinais na área de estudo. As ferramentas estatísticas utilizadas no estudo mostraram-se úteis para apontar as plantas mais importantes e específicas da categoria de doença. Plantas de alto valor de uso e as novas plantas medicinais relatadas podem ser uma importante fonte de isolamento de compostos farmacologicamente ativos.

Traditional knowledge about medicinal plant in the remote areas of Wari Tehsil, Dir Upper, Pakistan / Conhecimento tradicional sobre plantas medicinais nas áreas remotas de Wari Tehsil, Dir Upper, Paquistão

Abstract Traditional medicine is cheaper and easily available to local people, to care for most frequent diseases in the Northern parts of Pakistan. Our study aimed at inventorying medicine from local plants, documenting their uses, and assessing their market value in 2015-2018 during spring, summer, and winter seasons. A total of 15 trips were made, 5 in each season. Semi-structured interviews with 165 inhabitant's age range between 20-80 years were conducted, analyzed the data is analyzed using Relative frequency of citation(RFC), Use Value(UV), Fidelity Level(FL), Informants consensus factor(ICF), and Jaccard index(JI) to find the most frequent and well-known used species in the area. A total of 86 species belonging to 39 vascular plant families, 33 genera were documented as medicinally important. Family Asteraceae was observed as the dominant family among all the families with 10 species, the leaf was the most used parts and decoction 36% was the most preferred preparation type. Herb was the predominant life form (67%). The maximum UV (0.92) was demonstrated by J. adhatoda L. species, while A. sativum L. shows maximum RFC (0.58), the highest ICF value represented by diarrhea and dermatitis 0.92, and high FL value is recorded 100%. According to our collections, wild species were 45%, invasive species were 38% and cultivated 17% recorded, dicots species were recorded more 81%. Seven 7 medicinal species is being economically important and export to the local and international market of the world, whereas P. integrima L. species were the most exported species according to the local dealers. The investigated area is rural and the local people depend on the area's plants for their health needs, and other uses like a vegetable, fuelwood, fodder, etc. The current result of RFC, UV, ICF, FL, and JI shows that medicinal flora needs to be pharmacologically and phytochemically investigated to prove their efficacy. The documentation of medicinal knowledge is important to preserve this precious old knowledge before it is lost forever, due to technological and environmental changes in the world.

Resumo A medicina tradicional é mais barata e facilmente disponível à população local para cuidar das doenças mais frequentes nas áreas do norte do Paquistão. Nosso estudo teve como objetivo inventariar medicamentos de plantas locais, documentar seus usos e avaliar seu valor de mercado em 2015-2018 durante as temporadas de primavera, verão e inverno. Foram feitas 15 viagens, 5 em cada temporada. Foram realizadas entrevistas semiestruturadas com 165 moradores na faixa etária de 20 a 80 anos, com dados analisados ​​por meio de frequência relativa de citação (RFC), valor de uso (UV), nível de fidelidade (FL), fator de consenso de informantes (CIF), e o índice de Jaccard (JI) para encontrar as espécies utilizadas mais frequentes e conhecidas na área. Um total de 86 espécies pertencentes a 39 famílias de plantas vasculares, 33 gêneros foram documentados como medicamente importantes. A família Asteraceae foi observada como a família dominante entre todas as famílias com 10 espécies, a folha foi a parte mais utilizada e a decocção 36% foi o tipo de preparação mais preferido. A erva foi a forma de vida predominante (67%). O UV máximo (0,92) foi demonstrado pelas espécies de J. adhatoda L., enquanto A. sativum L. mostra RFC máximo (0,58), o maior valor de ICF representado por diarreia e dermatite 0,92, e alto valor de FL é registrado 100%. De acordo com nossas coleções, as espécies selvagens foram 45%, as espécies invasoras 38% e as cultivadas 17% registradas, as espécies dicotiledôneas foram registradas mais 81%. Sete espécies medicinais estão sendo economicamente importantes e exportadas para o mercado local e internacional do mundo, enquanto as espécies de P. integrima L. foram as espécies mais exportadas de acordo com os comerciantes locais. A área investigada é rural e a população local depende das plantas da área para suas necessidades de saúde e outros usos como vegetal, lenha, forragem etc. O resultado atual de RFC, UV, ICF, FL e JI mostra que a flora medicinal precisa ser investigada farmacológica e fitoquimicamente para comprovar sua eficácia. A documentação do conhecimento medicinal é importante para preservar esse precioso conhecimento antigo antes que se perca para sempre, devido às mudanças tecnológicas e ambientais do mundo.

Traditional knowledge about medicinal plant in the remote areas of Wari Tehsil, Dir Upper, Pakistan

Abstract Traditional medicine is cheaper and easily available to local people, to care for most frequent diseases in the Northern parts of Pakistan. Our study aimed at inventorying medicine from local plants, documenting their uses, and assessing their market value in 2015-2018 during spring, summer, and winter seasons. A total of 15 trips were made, 5 in each season. Semi-structured interviews with 165 inhabitants age range between 20-80 years were conducted, analyzed the data is analyzed using Relative frequency of citation(RFC), Use Value(UV), Fidelity Level(FL), Informants consensus factor(ICF), and Jaccard index(JI) to find the most frequent and well-known used species in the area. A total of 86 species belonging to 39 vascular plant families, 33 genera were documented as medicinally important. Family Asteraceae was observed as the dominant family among all the families with 10 species, the leaf was the most used parts and decoction 36% was the most preferred preparation type. Herb was the predominant life form (67%). The maximum UV (0.92) was demonstrated by J. adhatoda L. species, while A. sativum L. shows maximum RFC (0.58), the highest ICF value represented by diarrhea and dermatitis 0.92, and high FL value is recorded 100%. According to our collections, wild species were 45%, invasive species were 38% and cultivated 17% recorded, dicots species were recorded more 81%. Seven 7 medicinal species is being economically important and export to the local and international market of the world, whereas P. integrima L. species were the most exported species according to the local dealers. The investigated area is rural and the local people depend on the area's plants for their health needs, and other uses like a vegetable, fuelwood, fodder, etc. The current result of RFC, UV, ICF, FL, and JI shows that medicinal flora needs to be pharmacologically and phytochemically investigated to prove their efficacy. The documentation of medicinal knowledge is important to preserve this precious old knowledge before it is lost forever, due to technological and environmental changes in the world.

Resumo A medicina tradicional é mais barata e facilmente disponível à população local para cuidar das doenças mais frequentes nas áreas do norte do Paquistão. Nosso estudo teve como objetivo inventariar medicamentos de plantas locais, documentar seus usos e avaliar seu valor de mercado em 2015-2018 durante as temporadas de primavera, verão e inverno. Foram feitas 15 viagens, 5 em cada temporada. Foram realizadas entrevistas semiestruturadas com 165 moradores na faixa etária de 20 a 80 anos, com dados analisados por meio de frequência relativa de citação (RFC), valor de uso (UV), nível de fidelidade (FL), fator de consenso de informantes (CIF), e o índice de Jaccard (JI) para encontrar as espécies utilizadas mais frequentes e conhecidas na área. Um total de 86 espécies pertencentes a 39 famílias de plantas vasculares, 33 gêneros foram documentados como medicamente importantes. A família Asteraceae foi observada como a família dominante entre todas as famílias com 10 espécies, a folha foi a parte mais utilizada e a decocção 36% foi o tipo de preparação mais preferido. A erva foi a forma de vida predominante (67%). O UV máximo (0,92) foi demonstrado pelas espécies de J. adhatoda L., enquanto A. sativum L. mostra RFC máximo (0,58), o maior valor de ICF representado por diarreia e dermatite 0,92, e alto valor de FL é registrado 100%. De acordo com nossas coleções, as espécies selvagens foram 45%, as espécies invasoras 38% e as cultivadas 17% registradas, as espécies dicotiledôneas foram registradas mais 81%. Sete espécies medicinais estão sendo economicamente importantes e exportadas para o mercado local e internacional do mundo, enquanto as espécies de P. integrima L. foram as espécies mais exportadas de acordo com os comerciantes locais. A área investigada é rural e a população local depende das plantas da área para suas necessidades de saúde e outros usos como vegetal, lenha, forragem etc. O resultado atual de RFC, UV, ICF, FL e JI mostra que a flora medicinal precisa ser investigada farmacológica e fitoquimicamente para comprovar sua eficácia. A documentação do conhecimento medicinal é importante para preservar esse precioso conhecimento antigo antes que se perca para sempre, devido às mudanças tecnológicas e ambientais do mundo.

Ethnomedicinal uses of plants for various diseases in the remote areas of Changa Manga Forest, Pakistan.

This study aims at reporting the indigenous knowledge of the medicinal flora from the inhabitants of surroundings of the World's largest artificial planted forest "Changa Manga", Pakistan. Data were collected by direct interviews and group meetings from 81 inhabitants including 32 local healers having information regarding the use of indigenous medicinal plants over a period of one year. Different statistical tools were applied to analyze the data including Frequency citation (FC), Relative frequency citation (RFC), Use Value, Factor of informants consensus and fidelity level. This study reported 73 plant species belonging to 37 plant families and 46 genera. The majority of plant species belong to compositae family. The most commonly used medicinal plants were P. hysterophorus L., P. dactylifera L., S. indicum L, P. harmala L., P. emblica L., and A. indica A.Juss. The greatest number of species was used to cure gastrointestinal disorders. The highest fidelity level (68.18%) was of E. helioscopia to cure gastrointestinal disorders. Maximum fresh uses (17) were reported by C. dactylon (L.) Pars. While the highest number of species reporting fresh uses in similar number was 13. In this study, five novel plants are being reported for the first time in Pakistan for their ethnomedicinal worth. Our data reflect unique usage of the medicinal plants in the study area. The statistical tools used in the study proved useful in pointing the most important and disease category specific plants. High use value plant and the new reported medicinal plants might prove an important source of the isolation of pharmacologically active compounds.

Traditional knowledge about medicinal plant in the remote areas of Wari Tehsil, Dir Upper, Pakistan.

Traditional medicine is cheaper and easily available to local people, to care for most frequent diseases in the Northern parts of Pakistan. Our study aimed at inventorying medicine from local plants, documenting their uses, and assessing their market value in 2015-2018 during spring, summer, and winter seasons. A total of 15 trips were made, 5 in each season. Semi-structured interviews with 165 inhabitant's age range between 20-80 years were conducted, analyzed the data is analyzed using Relative frequency of citation(RFC), Use Value(UV), Fidelity Level(FL), Informants consensus factor(ICF), and Jaccard index(JI) to find the most frequent and well-known used species in the area. A total of 86 species belonging to 39 vascular plant families, 33 genera were documented as medicinally important. Family Asteraceae was observed as the dominant family among all the families with 10 species, the leaf was the most used parts and decoction 36% was the most preferred preparation type. Herb was the predominant life form (67%). The maximum UV (0.92) was demonstrated by J. adhatoda L. species, while A. sativum L. shows maximum RFC (0.58), the highest ICF value represented by diarrhea and dermatitis 0.92, and high FL value is recorded 100%. According to our collections, wild species were 45%, invasive species were 38% and cultivated 17% recorded, dicots species were recorded more 81%. Seven 7 medicinal species is being economically important and export to the local and international market of the world, whereas P. integrima L. species were the most exported species according to the local dealers. The investigated area is rural and the local people depend on the area's plants for their health needs, and other uses like a vegetable, fuelwood, fodder, etc. The current result of RFC, UV, ICF, FL, and JI shows that medicinal flora needs to be pharmacologically and phytochemically investigated to prove their efficacy. The documentation of medicinal knowledge is important to preserve this precious old knowledge before it is lost forever, due to technological and environmental changes in the world.

Comparison of the Copan WASPLab incorporating the BioRad expert system against the SIRscan 2000 automatic for routine antimicrobial disc diffusion susceptibility testing.

OBJECTIVES: This study investigated the agreement at the categorical level between the Copan WASPLab incorporating the BioRad expert system against the SIRscan 2000 automatic for antimicrobial disc diffusion susceptibility testing. METHODS: The 338 clinical strains (67 Pseudomonas aeruginosa, 19 methicillin-resistant Staphylococcus aureus, 75 methicillin-sensitive S. aureus and 177 Enterobacterales isolates) analysed in this study were non-duplicate isolates obtained from consecutive clinical samples referred to the clinical bacteriology laboratory at Geneva University Hospitals between June and August 2019. For the WASPLab the inoculum suspension was prepared in strict accordance with the manufacturer's instruction (Copan WASP srl, Brescia, Italy) by adding 2 mL of the 0.5 McFarland primary suspension used for the SIRscan analysis into a sterile tube filled with 4 mL of sterile saline (1:3 dilution). The inoculum (2 × 30 µL loop/spreader) was spread over the entire surface of Mueller-Hinton agar plates according to the AST streaking pattern defined by Copan. The antibiotic discs were dispensed by the WASP and inoculated media were loaded on conveyors for transfer to the automatic incubators. The plates were incubated for 16 h, and several digital images were acquired. Inhibition zone diameters were automatically read by the WASPLab and were adjusted manually whenever necessary. For the SIRscan 2000 automatic, the antimicrobial disc diffusion susceptibility testing was performed according to the EUCAST guidelines. The gradient strip method was used to resolve discrepancies. RESULTS: The overall categorical agreement between the compared methods reached 99.1% (797/804; 95% CI 98.2%-99.6%), 99.5% (1029/1034; 95% CI 98.9%-99.8%), and 98.8% (2798/2832; 95% CI 98.3%-99.1%) for P. aeruginosa, S. aureus and the Enterobacterales, respectively. CONCLUSIONS: WASPLab incorporating the BioRad expert system provides a fully automated solution for antimicrobial disc diffusion susceptibility testing with equal or better accuracy than other available phenotypic methods.

Frequency of impaired glucose tolerance and diabetes mellitus in subjects with fasting blood glucose below 6.1 mmol/L (110 mg/dL).

The diagnosis of diabetes mellitus by the available criteria is controversial and relies heavily on fasting glucose results. This cross-sectional study in 2010-2011 aimed to measure the frequency of impaired glucose tolerance and diabetes mellitus in 127 subjects having fasting blood glucose < 7.0 mmol/L and to measure the agreement between different standard diagnostic criteria. Subjects presenting to a laboratory for analysis of fasting blood glucose for excluding diabetes mellitus underwent a 2-hour 75 g oral glucose challenge. A total of 40.6% of subjects with fasting blood glucose from 5.6-6.0 mmol/L had abnormal glucose regulation on the basis ofthe gold standard glucose challenge. Agreement between American Diabetes Association and World Health Organization diagnostic criteria was only fair (kappa = 0.32). Abnormalities of glucose metabolism including impaired glucose tolerance and diabetes mellitus can exist at fasting blood glucose results < 6.1 mmol/L (110 mg/dL).

Patients' perspectives on injuries.

AIM AND METHODS: To assess the way different terms used to describe a fracture affect the understanding a patient has of that fracture. The perceived severity of the injury and how the patient expects to be treated were also recorded with a view to optimising patient understanding. RESULTS: There was a very significant difference between what doctors can potentially say and what the patient ultimately understood about the consultation. This could have a direct effect on the management the patient expects from the initial description and diagnosis. CONCLUSIONS: It is important that doctors in the emergency department use terminology that is understood by the patient, as well as emphasising the potential seriousness of the injury. It is possibly better therefore to use informed lay terminology such as 'a break in a bone' rather than more formal vocabulary such 'a fracture' when discussing the diagnosis and treatment options.

Views of specialist registrars on specialty care in the community: employment prospects and the need for additional training.

AIM: To obtain the views of specialist registrars on specialty care in the community. METHOD: Specialist registrars from five Deaneries in England completed an online questionnaire about their views on employment prospects, the role of specialty care in the community, and the need for additional training in this area. RESULTS: One hundred and twenty seven replies were received over a four week period. Thirty (24%) viewed their future employment prospects as consultants as poor or very worrying. Seventy seven (61%) specialist registrars considered that as consultants they will need to work directly in the community. Thirty nine of these (51%) considered the need to work close to patients directly in the community as either a "bad" or "very bad" development. However, 102 (80%) specialist registrars believed that they should receive training on the delivery of specialty care in the community and 96 (76%) wanted this in the form of a university based degree.

Interaction of CR6 (GADD45gamma ) with proliferating cell nuclear antigen impedes negative growth control.

GADD45, MyD118, and CR6 (also termed GADD45alpha, beta, and gamma) comprise a family of genes that encode for related proteins playing important roles in negative growth control, including growth suppression. Data accumulated suggest that MyD118/GADD45/CR6 serve similar but not identical functions along different apoptotic and growth suppressive pathways. It is also apparent that individual members of the MyD118/GADD45/CR6 family are differentially induced by a variety of genetic and environmental stress agents. The MyD118, CR6, and GADD45 proteins were shown to predominantly localize within the cell nucleus. Recently, we have shown that both MyD118 and GADD45 interact with proliferating cell nuclear antigen (PCNA), a protein that plays a central role in DNA replication, DNA repair, and cell cycle progression, as well as with the universal cyclin-dependent kinase inhibitor p21. In this work we show that also CR6 interacts with PCNA and p21. Moreover, it is shown that CR6 interacts with PCNA via a domain that also mediates interaction of both GADD45 and MyD118 with PCNA. Importantly, evidence has been obtained that interaction of CR6 with PCNA impedes the function of this protein in negative growth control, similar to observations reported for MyD118 and GADD45.

Characterization of MyD118, Gadd45, and proliferating cell nuclear antigen (PCNA) interacting domains. PCNA impedes MyD118 AND Gadd45-mediated negative growth control.

MyD118 and Gadd45 are related genes encoding for proteins that play important roles in negative growth control, including growth suppression and apoptosis. MyD118 and Gadd45 are related proteins that previously were shown to interact with proliferating cell nuclear antigen (PCNA), implicated in DNA replication, DNA repair, and cell cycle progression. To establish the role of MyD118 and Gadd45 interactions with PCNA, in this work we sought to identify the interacting domains and analyze the significance of this interaction in negative growth control. Using complementary in vivo and in vitro interaction assays the N-terminal (1-46) and middle (100-127) regions of PCNA were identified as harboring MyD118- and Gadd45 interacting domains, whereas PCNA interacting domains within MyD118 and Gadd45 were localized to the C termini of these proteins (amino acids 114-156 and 137-165, respectively). These findings provide first evidence that similar domains within MyD118 and Gadd45 mediate interactions with PCNA. Importantly, ectopic expression of MyD118 or Gadd45 N-terminal peptides, lacking the PCNA interacting domain, was found to suppress colony formation or induce apoptosis more efficiently than the full-length proteins. These findings suggest that interaction of MyD118 or Gadd45 with PCNA, in essence, serves to impede negative growth control.

A retrospective study of unerupted maxillary incisors associated with supernumerary teeth.

We retrospectively reviewed the clinical records and radiographs of 100 patients who had had supernumerary teeth removed. Their mean (SD) age was 9 years 3 months (2). The 100 patients had a total of 127 unerupted maxillary incisors associated with supernumerary teeth. The supernumerary tooth was removed without exposure of the permanent tooth more often among the 79 younger children (aged 10 years or less) (SND=3.52, P<0.01), and when the incisors were less mature (Cvek classification 1, 2, and 3) (SND=5.27, P<0.01). Of these incisors with immature roots that were treated conservatively, 60 (72%) erupted and 24 (28%) required further operation. Of the mature incisors treated conservatively, 10 (63%) required further operation. In this study, almost three-quarters of immature incisors erupted spontaneously after removal of the associated supernumerary teeth. Over half of the mature teeth required further operation. Mature teeth should be exposed with or without bonding at the time of removal of the supernumerary teeth.

CR6: A third member in the MyD118 and Gadd45 gene family which functions in negative growth control.

MyD118 and Gadd45 are two related genes which encode for proteins that play important roles in negative growth control, including both growth suppression and apoptosis. A strategy was employed to clone new members of the MyD118 and Gadd45 family of genes. Based on alignment of the deduced amino acid sequences, one cDNA clone was found to encode for the murine homologue of human CR6, originally cloned as an IL-2 immediate-early response gene. The murine and human CR6 proteins were observed to be 97% identical, indicating that CR6 is an evolutionarily conserved protein. Analysis of CR6 expression during hematopoietic cell development associated with growth arrest and apoptotic cell death, upon exposure of hematopoietic cells to a variety of growth arrest and apoptotic stimuli, and in a variety of murine tissues, has revealed that CR6 expression differs significantly from the expression of the related MyD118 and Gadd45 genes. Nevertheless, CR6, like MyD118 and Gadd45, suppressed colony formation of human lung carcinoma H1299 cells. These data suggest that CR6 plays similar, but not identical, roles to MyD118 and Gadd45 in negative control of cell growth.

Charge and solvation effects in anion recognition centers: an inquiry exploiting reactive arginines.

Following a long-standing suggestion of Riordan et al. [Riordan, J. F., McElvany, K. D., and Borders, C. L., Jr. (1977) Science 195, 884-885], we sought to exploit chemically activated arginines as probes to characterize the microenvironmental effects in enzymes that mediate the recognition of anionic substrates. A micellar simulation study establishes that octylguanidine (OGn) becomes chemically activated upon incorporation into both cetyltrimethylammonium bromide (CTAB) and Triton X-100 micelles and that the activations correlate with the pKa diminutions induced in its guanidinium group by the effects of electrostatic or nonelectrostatic nature as reflected in the results of pH and salt titration experiments. Next, a protein modification study establishes that the modifiable arginines in a number of enzymes also have diminished pKa's, again due to effects of electrostatic or nonelectrostatic nature as reflected in the results of pH and salt titration experiments. Warwicker's finite difference Poisson--Boltzmann algorithm [Warwicker, J. (1992) J. Mol. Biol. 223, 247-257] is applied to several of the enzymes with available crystal structure coordinates, and indeed, their chemically activated arginines are found to be in an electrostatic microenvironment that can diminish their pKa's, with the magnitudes of these diminutions matching closely the diminutions measured experimentally. Finally, the chemically activated arginines are examined with respect to their atomic atmosphere and are thus found to occur in a local microenvironment that would facilitate their roles as anion anchors. Thus, electrostatic and solvation effects are found to be critical determinants of the arginine role as an anion anchor.

Topological analysis of the role of homology in Flp-mediated recombination.

Recombination by the Flp recombinase of Saccharomyces cerevisiae is known to be inhibited by heterology of the overlap regions of the two recombining DNA targets (FRT sites). We have used topological analysis to show that Flp can promote two rounds of intramolecular recombination between heterologous FRT sites contained within the same supercoiled plasmid. The products are in parental nonrecombinant configuration. Thus, heterology may appear to "block" recombination by rendering the heteroduplex recombinant products unstable, thus favoring a second round of recombination to homoduplex (but parental) products. Hence, homology in the core region is not a requirement for the recombination reaction by Flp but for the formation of recombinant products.