scholarly journals Biological attributes of the kissing bug Triatoma rubrofasciata from Vietnam

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Ho Viet Hieu ◽  
Le Thanh Do ◽  
Sebastián Pita ◽  
Hoang Ha ◽  
Pham Thi Khoa ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Natural Infection ◽  
Public Health Problem ◽  
Food Sources ◽  
Hatching Rate ◽  
Starvation Resistance ◽  
Genetic Characteristics ◽  
Central Vietnam ◽  
Biological Attributes ◽  
Triatoma Rubrofasciata

Abstract Background Triatoma rubrofasciata is the only kissing bug species distributed globally. In the Americas, this species transmits the parasite Trypanosoma cruzi, responsible for Chagas disease. The presence of T. rubrofasciata in several Asian countries has greatly increased recently. In Vietnam, it is found in large numbers, closely associated with human environments. Although T. rubrofasciata from Asia is not infected with Tryp. cruzi, it carries other parasites such as Trypanosoma lewisi and Trypanosoma conorhini. Reports of bites by T. rubrofasciata have increased significantly in several places of Vietnam, becoming a public health problem as it produces severe anaphylactic reactions. Methods Specimens of T. rubrofasciata were collected from seven provinces in central Vietnam. We analyzed different biological attributes (life-cycle, starvation resistance, feeding and reproductive capacities) and genetic characteristics (chromosomes and DNA sequences) of T. rubrofasciata from Vietnam and compared them with Brazilian specimens. Natural infection with Tryp. conorhini and Tryp. lewisi were analyzed in a sample of 100 collected insects. Results Species identification of T. rubrofasciata from central Vietnam was corroborated by genetic markers. Cytogenetic analyses showed that T. rubrofasciata from central Vietnam share the same chromosomal characteristics with individuals from Brazil and Hanoi. DNA sequence analyses of a mitochondrial cytochrome b gene fragment showed little variation between Old and New World specimens. Our study sample, compared with Brazilian individuals, showed a higher survival capacity revealed by a higher hatching rate (98% compared with 80.5%), a larger amount of blood taken in single meal and long-term starvation resistance. Furthermore, this species had a high natural rate of infection with Tryp. conorhini (46%) and Tryp. lewisi (27%). Conclusions For T. rubrofasciata of Vietnam, a high rate of fecundity throughout the year, a high capacity for starvation, and its occurrence in synanthropic environments of urban areas with a high availability of food sources are risk factors to be taken into account by vector control campaigns. The several allergic reactions caused by their bites and their high infection with Tryp. lewisi highlight the need to implement specific control programmes for T. rubrofasciata in Vietnam.

scholarly journals Community Assessment of Availability, Consumption, and Cultural Acceptability of Food Sources of (PRO)Vitamin A: Toward the Development of a Dietary Intervention among Preschool Children in Rural Burkina Faso

2005 ◽  
Vol 26 (4) ◽  
pp. 356-365 ◽  
Author(s):  
Constance P. Nana ◽  
Inge D. Brouwer ◽  
Noel-Marie Zagré ◽  
Frans J. Kok ◽  
Alfred S. Traoré
Keyword(s):  
Vitamin A ◽  
Burkina Faso ◽  
Rural Areas ◽  
Dietary Intervention ◽  
Vitamin A Deficiency ◽  
Public Health Problem ◽  
Ethnographic Study ◽  
Leafy Vegetables ◽  
Food Sources ◽  
Green Leafy Vegetables

Background Vitamin A deficiency remains a public health problem in Burkina Faso and elsewhere in the developing world. Dietary diversification is a promising strategy that needs to be explored to strengthen the country's ongoing supplementation program. Objective The purpose of this study was to identify locally available and acceptable (pro)vitamin A–rich foods to be included in a dietary intervention addressing vitamin A deficiency in children aged six months to three years. Methods A food ethnographic study combining recall methods, observation, and focused group discussion was conducted in the dry and rainy seasons. Thirty-five mother–child pairs were randomly selected and included in the study. Results The dietary pattern of children was characterized by low diversity with extremely low energy and vitamin A intake in both seasons. The study identified the availability of numerous (pro)vitamin A–rich foods, but these foods are either not consumed or consumed by few in low amounts and/or in low frequencies. The main constraining factors identified are related to financial accessibility (for liver), seasonal availability (for egg, milk, mango, papaya, and green leafy vegetables), and beliefs related to consumption and preparation (for green leafy vegetables). However, the study also revealed that the study population associated all identified (pro)vitamin A–rich foods with positive attributes such as health, strength, and vitamin richness, which might offer an entry point for designing and implementing dietary interventions. Conclusions Based on the findings of this formative research, intervention strategies with mango and liver are proposed to improve the vitamin A intake and status of children in the rural areas of Burkina Faso.

scholarly journals Genomic Analysis of the Emergence of Vancomycin-Resistant Staphylococcus aureus

mBio ◽  
2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Scott D. Kobayashi ◽  
James M. Musser ◽  
Frank R. DeLeo
Keyword(s):  
United States ◽  
Staphylococcus Aureus ◽  
Dna Sequences ◽  
Clonal Complex ◽  
Infectious Agent ◽  
The United States ◽  
Vancomycin Resistance ◽  
Genetic Characteristics ◽  
Content Type ◽  
Vancomycin Resistant

ABSTRACT Staphylococcus aureus is a human commensal bacterium and a prominent cause of infections globally. The high incidence of S. aureus infections is compounded by the ability of the microbe to readily acquire resistance to antibiotics. In the United States, methicillin-resistant S. aureus (MRSA) is a leading cause of morbidity and mortality by a single infectious agent. Therapeutic options for severe MRSA infections are limited to a few antibiotics to which the organism is typically susceptible, including vancomycin. Acquisition of high-level vancomycin resistance by MRSA is a major concern, but to date, there have been only 12 vancomycin-resistant S. aureus (VRSA) isolates reported in the United States and all belong to a phylogenetic lineage known as clonal complex 5. To gain enhanced understanding of the genetic characteristics conducive to the acquisition of vancomycin resistance by S. aureus , V. N. Kos et al. performed whole-genome sequencing of all 12 VRSA isolates and compared the DNA sequences to the genomes of other S. aureus strains. The findings provide new information about the evolutionary history of VRSA and identify genetic features that may bear on the relationship between S. aureus clonal complex 5 strains and the acquisition of vancomycin resistance genes from enterococci.

scholarly journals Natural infection and vertical transmission of two flaviviruses (Yellow fever and Zika) in mosquitoes in primary forests in the Brazilian state of Rio de Janeiro (Diptera: Culicidae)

2019 ◽  
Author(s):  
Jeronimo Alencar ◽  
Cecilia Ferreira de Mello ◽  
Carlos Brisola Marcondes ◽  
Anthony Érico Guimarães ◽  
Helena Keiko Toma ◽  
...  
Keyword(s):  
South America ◽  
Vertical Transmission ◽  
Yellow Fever ◽  
Yellow Fever Virus ◽  
Natural Infection ◽  
Public Health Problem ◽  
Correct Result ◽  
Natural Forests ◽  
American Continent ◽  
Human Interference

AbstractBackgroundZika virus (ZIKV) was recently introduced in the American continent, probably transmitted by Aedes aegypti and possibly by Ae. albopictus and Culex quinquefasciatus in urban environments. ZIKV represents a known public health problem as it has been involved in newborn cases of congenital microcephaly in South America since 2005. The transmission of this virus in forested areas of other countries and its relative ubiquity in relation to its vectors and reservoirs raises suspicions of its adaptation to non-human modified environments (i.e., natural forests reserve) or on this continent, similar to those seen for Yellow fever virus (YFV). The objective of this work was to have an epidemiological monitoring tool mapping insects as well as circulating arboviruses in wild areas with low human interference. This study was based on the history of the insect flavivirus spreading cycle.Methods/Principal FindingsUsing a previously described sensitive PCR-based assay to assess the conserved NS5 region of the Flavivirus genus, both YFV partial genome and ZIKV were found in pools of Aedes albopictus, a sylvatic mosquito adapted to human-modified environments, and in Haemagogus leucocelaenus, a sylvatic mosquito.ConclusionsThis is the first report of natural infection by ZIKV in mosquitoes in a sylvatic environment on the American continent. The wide distribution of these mosquitoes is probably important in the transmission of ZIKV. Vertical transmission indicates a higher efficiency for the maintenance and transmission of the virus in nature as well as the presence of the ZIKV in permanent character in the forest areas as it occurs with the YFV thus making more difficult the prevention of new cases of Zika in humans.Author SummaryArboviruses are diseases transmitted by arthropod vectors, hence the origin of the term ARthropod BOrne VIRUS, which is adopted since 1942. This work had as objective to survey the circulating insects as well as to detect the presence of viruses in them. Arboviruses circulate between insects and vertebrate hosts, having importance for promoting diseases in humans and animals. The diseases most known at the time, due to the recent cases reported by South America, are Dengue, Zika, Yellow Fever and Chikungunya. For this study, we used appropriate traps to collect the insects and their eggs in wild areas where there is little human interference. After collection, mosquitoes and / or eggs were identified and separated as to the source and species. The eggs were kept in laboratory conditions for the hatching of new insects. All the insects obtained were separated into pools to be macerated and thus extract the RNA from the viruses to be studied. Using molecular biology techniques, in our case the RT-PCR (Reverse Transcriptase Polymerase Chain Reaction), we amplified the RNA and in sequentially, we performed the sequencing reaction. With sequencing, it is possible to identify which virus material is present since each virus has a characteristic arrangement. For the identification of the sequences, we need to use some computational programs that guarantee us the correct result.

scholarly journals Biological attributes of diapausing and non-diapausing Doryctobracon areolatus (Hymenoptera, Braconidae), a parasitoid of Anastrepha spp. (Diptera, Tephritidae) fruit flies

2020 ◽  
Vol 78 ◽  
pp. 41-56
Author(s):  
Jassmin Cruz-Bustos ◽  
Pablo Montoya ◽  
Gabriela Pérez-Lachaud ◽  
Javier Valle-Mora ◽  
Pablo Liedo
Keyword(s):  
Female Offspring ◽  
Developmental Time ◽  
Fruit Flies ◽  
Pupal Weight ◽  
Adult Longevity ◽  
Anastrepha Ludens ◽  
Starvation Resistance ◽  
Flight Ability ◽  
Laboratory Colony ◽  
Biological Attributes

Doryctobracon areolatus (Szépligeti), a solitary endoparasitoid native to the Neotropics, attacks eggs and early instar larvae of Anastrepha fruit flies, and can enter diapause under tropical and subtropical conditions. We aimed to test if biological attributes, such as size, flight ability, starvation resistance, longevity and fecundity of diapausing individuals differ from those of non-diapausing ones. Parasitoids were obtained from a laboratory colony reared on Anastrepha ludens (Loew) larvae. Parasitized host puparia were sorted in two cohorts according to their diapause condition. Developmental time from egg to adult ranged from 18 to 31 days in non-diapausing parasitoids, and 70 to 278 days for diapausing individuals. Pupal weight and adult measurements were higher in non-diapausing than in diapausing parasitoids. There were no differences in adult longevity, starvation resistance, and emergence between diapausing and non-diapausing wasps. Flight ability and fecundity rates were greater in the non-diapausing than in the diapause cohort. The proportion of female offspring was greater in the non-diapausing cohort (42.5%), whereas in the diapausing cohort the male offspring proportion was greater (62.4%). Both cohorts produced diapause offspring, but the non-diapausing cohort produced more (26.6%) than the diapausing one (9.1%). Maternal age had a significant effect on the proportion of diapause offspring: in 26 to 34 days old non-diapausing females, 78.9% of their offspring entered into diapause. These results confirmed that diapause affects the biological attributes of D. areolatus. The observed differences contribute to better understand the diapause influence on the colonization and rearing process of this species and its use as biocontrol agent.

scholarly journals Shiga toxin-producing Escherichia coli (STEC) food-borne outbreaks

2017 ◽  
Vol 63 (1) ◽  
pp. 45 ◽  
Author(s):  
A. PEXARA (Α. ΠΕΞΑΡΑ) ◽  
A. S. ANGELIDIS (Α. Σ. ΑΓΓΕΛΙΔΗΣ) ◽  
A. GOVARIS (Α. ΓΚΟΒΑΡΗΣ)
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Intestinal Flora ◽  
Food Poisoning ◽  
Significant Risk ◽  
Public Health Problem ◽  
Human Infection ◽  
Food Sources ◽  
E Coli ◽  
Food Borne

Escherichia coli (E. coli) are Gram negativo, non-sporulating bacteria, which belong to the normal intestinal flora of humans and animals. Shiga toxin-producing E. coli (STFC) arc a group of if. coli that is defined by the capacity to produce toxins called Shiga toxins (Stx). hollowing ingestion of STEC, the significant risk of two serious and potentially life-threatening complications of infection, hemorrhagic colitis and hemolytic uremic syndrome (HUS), makes STHC food poisoning a serious public health problem. Besides Stx, human pathogenic STFC harbor additional virulence factors that are important for their pathogenicity. Although human infection may also be acquired by direct transmission from person to person or by direct contact of humans with animal carriers, the majority of STFC infections are food-borne in origin.The gastrointestinal tract of healthy ruminants seems to be the foremost important reservoir for STFC and ingestion of undercooked beef one of the most likely routes of transmission to humans, Other important food sources include faecally contaminated vegetables and drinking water, The serogroup classification of STHC is based on the somatic (O) and flagellar (H) antigens, and, to date, more than 200 STFC serogroups have been identified, Human STFC infections are, however, associated with a minor subset of 0;H serotypes. Of these, the 0157:H7 or the 0157 :H- serogroups (STFC 0157) are the ones most frequently reported to be associated with food-borne outbreaks. However other non-0157 STFC serogroups such as E. coli 026, 0103, O l l i , 012I, 045 and 0145 have caused several outbreaks in recent years.Two outbreaks of gastroenteritis caused by E. coli 0157:117 were first reported in the US, following the consumption of undercooked hamburgers, in 1982. Since then several outbreaks were reported worldwide. A major E. coli 0157:117 outbreak occurred in Japan and contaminated radish sprouts was identified as the vehicle of infection. More than 6,000 school children were affected, 101 people were hospitalized with lILS and 12 deaths were recorded. The recent outbreak of STFC 0104:114 infection and HUS reported in Germany in the spring of 2011 was one of the largest outbreaks worldwide. As of 27 July, 3 126 cases of STFC infections, 773 cases of HUS including 46 deaths linked to the outbreak in Germany and occurring in the Furopean Union (FU) (including Norway), Outside the FU 8 cases of STFC and 5 cases of HUS, including 1 death have been reported in the USA, Canada and Switzerland, all with recent travel history to Germany.The present review on major STliC food-borne outbreaks recorded worldwide highlights the need for eontrol measures in order to prevent or at least minimize the occurrence of similar events in the future.

Effects of food sources on the fecundity and gene expression of vitellogenin and its receptor from Amblyseius eharai (Acari: Phytoseiidae)

2020 ◽  
Vol 25 (1) ◽  
pp. 139-154
Author(s):  
Ji Wang ◽  
Tianrong Xin ◽  
Xianyan Ye ◽  
Xinyu Huang ◽  
Shangren Gao ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Amino Acid Sequences ◽  
Open Reading Frames ◽  
Reproductive Capacity ◽  
Food Sources ◽  
Hatching Rate ◽  
Neoseiulus Cucumeris ◽  
Reproductive Process ◽  
Arthropod Species ◽  
Positive Correlations

Vitellogenin (Vg) and Vitellogenin receptor (VgR) play key roles in the reproductive process and development of many arthropod species, including Amblyseius eharai, a dominant natural enemy of spider mites and other small pests. In this study, impacts of different food on A. eharai fecundity were investigated. Two Vg genes (AeVg1 and AeVg2) and AeVgR genes were cloned, with their expression pattern analyzed. When fed with different foods including Tetranychus cinnabarinus, Aleuroglyphus ovatus and Camellia oleifera pollen, the number of eggs for each female of A. eharai was influenced significantly (P<0.05), while the hatching rate of eggs not significantly (P>0.05). The open reading frames of AeVg1, AeVg2 and AeVgR were 5673, 5634 and 5597 bp, encoding 1857, 1851 and 1830 amino acids, respectively. Phylogenetic analysis of the amino acid sequences between the AeVgs and AeVgR and 35 other Vg and VgRs from other arthropod species showed that A. eharai AeVg1 was related most closely to Neoseiulus barkeri Vg1, AeVg2 was related most closely to Neoseiulus cucumeris Vg2, AeVgR was most similar to Varroa jacobsori VgR. AeVgs and AeVgR had similar expression patterns: the highest expression was observed in the oviposition female stage, and the highest expression was observed in A. eharai fed with C. oleifera pollen. Positive correlations between expression of AeVgs and AeVgR and fecundity were observed. These results will help us understand the molecular mechanism of the reproductive capacity in A. eharai.

DISTRIBUTION OF TRIATOMINES (HETEROPTERA: REDUVIIDAE) ASSOCIATED WITH HUMAN HABITATION AND POTENTIAL RISK AREAS IN SIX STATES OF THE MEXICAN REPUBLIC

2020 ◽  
Vol 5 ◽  
Author(s):  
José Ismael Benítez-Alva ◽  
Herón Huerta ◽  
Juan Luis Téllez-Rendón
Keyword(s):  
Public Health ◽  
Latin America ◽  
Trypanosoma Cruzi ◽  
Potential Risk ◽  
Health Problem ◽  
Natural Infection ◽  
Public Health Problem ◽  
Distribution Maps ◽  
Risk Areas ◽  
Human Habitation

Chagas disease is a real public health problem in Latin America, caused by the flagellate protozoan<br />Trypanosoma cruzi and described by Carlos Chagas in 1909. T. cruzi is transmitted by bloodsucking<br />insects of the subfamily Triatominae which thrive in sylvatic, peridomestic, and domestic habitats,<br />being in the latter two a potential risk to public health because of their role as vectors. We review the<br />distribution of triatomines associated with human habitation and their natural infection with T. cruzi<br />from the states of Aguascalientes, Chiapas, Guerrero, Jalisco, Michoacán, and Oaxaca. Based on<br />samples received in the Laboratory of Entomology of the Institute of Epidemiological Diagnosis and<br />Reference (InDRE-SSA) during the period 2006 to 2010, distribution maps and stratification of potential<br />areas of risk were made. A total of 1910 specimens of seven species of triatomines were identified.<br />Triatoma barberi, Meccus longipennis and M. pallidipennis were the species with the highest rate of<br />infection with T. cruzi; M. pallidipennis and T. dimidiata were the most widely distributed species.

Gender loci in DNA forensics and women's sports

Biomics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 54-74
Author(s):  
R.R. Garafutdinov ◽  
A.R. Sakhabutdinova ◽  
Ya.I. Alekseev ◽  
A.V. Chemeris
Keyword(s):  
Y Chromosome ◽  
Forensic Medicine ◽  
Dna Sequences ◽  
Female Athletes ◽  
Ethical Issues ◽  
False Negative ◽  
Pcr Analysis ◽  
Women's Sports ◽  
Genetic Characteristics ◽  
Women’S Sports

In forensic medicine, it is necessary to establish the sexual identity of the owner of the analyzed biological material. To do this, it is necessary to use PCR to detect specific DNA sequences that are characteristic only of the Y chromosome. For these purposes, a number of loci are used, located on both the Y and X chromosomes but carrying certain differences in the nucleotide sequences (alpha satellites DYZ and DXZ; amelogenin loci AMELY and AMELX; STS steroid sulfatase genes; the genes of the neuroligin NLG4Y and NLG4X, etc.), and those located only on the Y-chromosome (sex-determining region SRY; gene of the specific testicular protein TSPY, etc.). At the same time, forensic experts often deal with damaged or old samples in which the DNA has been destroyed and extended fragments in it may simply not be, as a result of which false negative results will be formed. Thus, in DNA forensics, when detecting gender loci, the sizes of amplicons should tend to the minimum possible. Therefore, in this review article, a certain emphasis was placed on the size of amplicons, and as practice shows, for most loci, their minimization is in demand. Moreover, such a PCR analysis in a number of cases (in XX-men, XY-women, in persons with other sex chromosome abnormalities, in people who deliberately changed their gender identity) it can lead to a false definition of the phenotypic sex due to the genetic characteristics of such individuals. As a result, the ongoing investigation of a crime, focused on the search for a representative of a particular gender, can go down the wrong path. A cardinal solution to this problem in DNA criminology can be a universal DNA registration of the entire population, which will allow for the biological traces with high accuracy to establish a specific person to whom these traces belong and his real sex will no longer be important and it will not be relevant to determine it with the help of PCR. In addition to forensic medicine, the problem of establishing gender also exists in women's sports. For a whole decade, the PCR method and some of the loci listed above were used for this purpose, but since 2011 PCR has been abandoned and instead the level of the male hormone testosterone has became determined. However, with the gender of female athletes, there are much more ethical issues than genetic ones.

Molecular and morphological variation of Paragonimus westermani in Vietnam with records of new second intermediate crab hosts and a new locality in a northern province

Parasitology ◽  
2016 ◽  
Vol 143 (12) ◽  
pp. 1639-1646 ◽  
Author(s):  
N. PHAM DOANH ◽  
A. LUU TU ◽  
T. DUNG BUI ◽  
T. HO LOAN ◽  
NARIAKI NONAKA ◽  
...  
Keyword(s):  
Morphological Variation ◽  
Dna Sequences ◽  
Northern Region ◽  
Its2 Region ◽  
Paragonimus Westermani ◽  
Biological Features ◽  
The North ◽  
16S Gene ◽  
Central Vietnam ◽  
High Prevalence

SUMMARYParagonimus westermani is one of the most medically important lung flukes and is widely distributed in Asia. It exhibits considerable variation in morphological, genetic and biological features. In central provinces of Vietnam, a high prevalence of metacercariae of this species has been reported from the crab intermediate host, Vietopotamon aluoiense. In this study, we detected P. westermani metacercariae in two additional crab hosts, Donopotamon haii in Quang Tri Province, central Vietnam and Indochinamon tannanti in Yen Bai Province in the north. The latter is a new locality for P. westermani in a northern region of Vietnam where P. heterotremus is the only species currently known to cause human paragonimiasis. Paragonimus westermani metacercariae found in Vietnam showed considerable morphological variation but slight genetic variation based on DNA sequences from the nuclear ribosomal ITS2 region and the mitochondrial 16S gene. Co-infection of the same individual crabs with P. westermani and P. heterotremus and/or some other Paragonimus species was found frequently, suggesting potential for co-infection in humans. The findings of the present study emphasize the need for highly specific molecular and immunodiagnostic methods to differentially diagnose between P. westermani and P. heterotremus infections.

scholarly journals Identification of rad27 Mutations That Confer Differential Defects in Mutation Avoidance, Repeat Tract Instability, and Flap Cleavage

2001 ◽  
Vol 21 (15) ◽  
pp. 4889-4899 ◽  
Author(s):  
Yali Xie ◽  
Yuan Liu ◽  
Juan Lucas Argueso ◽  
Leigh A. Henricksen ◽  
Hui-I Kao ◽  
...  
Keyword(s):  
Dna Replication ◽  
Dna Sequences ◽  
Critical Role ◽  
Exonuclease Activity ◽  
Endonuclease Activity ◽  
Genetic Characteristics ◽  
Repeat Tract ◽  
Mutation Avoidance ◽  
Dna Replication And Repair ◽  
Mutant Phenotypes

ABSTRACT In eukaryotes, the nuclease activity of Rad27p (Fen1p) is thought to play a critical role in lagging-strand DNA replication by removing ribonucleotides present at the 5′ ends of Okazaki fragments. Genetic analysis of Saccharomyces cerevisiae also has identified a role for Rad27p in mutation avoidance. rad27Δ mutants display both a repeat tract instability phenotype and a high rate of forward mutations to canavanine resistance that result primarily from duplications of DNA sequences that are flanked by direct repeats. These observations suggested that Rad27p activities in DNA replication and repair could be altered by mutagenesis and specifically assayed. To test this idea, we analyzed two rad27alleles, rad27-G67S and rad27-G240D, that were identified in a screen for mutants that displayed repeat tract instability and mutator phenotypes. In chromosome stability assays,rad27-G67S strains displayed a higher frequency of repeat tract instabilities relative to CAN1 duplication events; in contrast, the rad27-G240D strains displayed the opposite phenotype. In biochemical assays, rad27-G67Sp displayed a weak exonuclease activity but significant single- and double-flap endonuclease activities. In contrast, rad27-G240Dp displayed a significant double-flap endonuclease activity but was devoid of exonuclease activity and showed only a weak single-flap endonuclease activity. Based on these observations, we hypothesize that the rad27-G67S mutant phenotypes resulted largely from specific defects in nuclease function that are important for degrading bubble intermediates, which can lead to DNA slippage events. Therad27-G240D mutant phenotypes were more difficult to reconcile to a specific biochemical defect, suggesting a structural role for Rad27p in DNA replication and repair. Since the mutants provide the means to relate nuclease functions in vitro to genetic characteristics in vivo, they are valuable tools for further analyses of the diverse biological roles of Rad27p.

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