Genetic control of "flor" formation by Saccharomyces.
The results described indicate that in Saccharomyces sp. the formation of "flor" is under the control of a single Mendelian gene for which is proposed the symbol "Fl."
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The results described indicate that in Saccharomyces sp. the formation of "flor" is under the control of a single Mendelian gene for which is proposed the symbol "Fl."
Blood samples from 509 Macushi (3 villages) and 623 Wapishana (11 villages) of Northern Brasil and Southern Guyana have been analyzed with respect to the phenotype and gene frequencies at the following 12 polymorphic loci: ABO, Kell-Cellano, MNSs, Rh, P, Duffy, Kidd, Diego, Lewis, Group-specific component, and the immunoglobulin allotypes of the Gm and Inv systems. The data suggest that 5-6% of the Wapishana gene pool is derived from non-Indians but only 1-2% of the Macushi. Inter- and intratribal genetic distances between villages are calculated for these data in an effort to understand gene flow between the tribes and to account for the unusual distribution of a newly-discovered genetic polymorphism of erythrocyte esterase A thus far limited to these 2 tribes (Neel et al., 1977). The data are puzzling and consistent with the possibility that both the Carib-speaking Macushi and the Arawak-speaking Wapishana have derived the esterase A allele in question from some third group now extinct or thus far undiscovered. Intertribal genetic distances based on gene frequencies at 6 loci are derived for 20 Amerindian tribes (including these 2); the "central" position of these 2 tribes can in part be explained by the active migration matrix connecting them.
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Thirty female Sprague-Dawley rats (250 +/- 10 g) were divided randomly into five equal groups. After overnight fasting, a silastic catheter was placed in the jugular vein of each rat. Each group was intragastrically administered 0.25 mg F/250 g rat weight in 1 ml of one of the following forms of fluoride supplements: Pediaflor (Abbott/Ross, Columbus, OH), Tri-Vi-Flor, Tri-Vi-Flor + iron; Poly-Vi-Flor or Poly-Vi-Flor + iron (Mead Johnson Nutritionals, Bristol-Myers Squibb Co., Evansville, IN). Timed blood samples were collected and plasma fluoride concentration was determined using the microdiffusion method. The presence of iron and vitamins affect the bioavailability of fluoride as measured by the area under the time-plasma fluoride concentration curve.
Most of the yeast strains of industrial interest are homothallic, which makes genetic analysis as well as improvement of their desirable properties extremely difficult. In this work, all the wine yeasts analyzed, except for two "flor" yeasts which were able to generate heterothallic meiotic products, were homozygous for the HO allele of homothallism. The genetic analysis of one of the "flor" yeast spores, which was heterothallic, indicated that the strain carried an HO allele of homothallism and that its heterothallic behaviour was due to a genetic constitution HML MAT HMR HO. This HO allele of the "flor" yeast behaved differently from other HO alleles present in the wine yeasts. It gave rise to a very retarded homothallism, with formation of selfzygotes which presented an abnormal morphology. These zygotes generated selfdiploids whose ability to sporulate was very inefficient. The lag in the expression of the homothallism allowed the isolation of hybrids between meiotic products of the "flor" yeasts and heterothallic laboratory strains with a frequency of 10(-1), as compared to that of the meiotic products of other wine yeasts, which was of 10(-4) to 10(-6). This result indicates that, among other factors which could influence the frequency of hybrid formation, the lag in the expression of homothallism could be the most important one. The use of heterothallic laboratory strains of mating type as opposed to a strain of alpha mating type, as well as the frequency of viable nucleus in the hybrid zygote after conjugation, also seemed to influence the success of hybrid formation between laboratory strains and the wine homothallic strains used.
Antibiotic-resistant bacteria are spreading in clinical, industrial, and environmental ecosystems. The spreading dynamics to and from the environment are unknown, largely due to the lack of appropriate (robust, fast, low-cost) analytical assays. In this study, we developed C12a, a versatile molecular toolbox to detect genetic markers of antibiotic resistance using CRISPR/Cas12a. Biochemical characterization show that the C12a toolbox can detect less than 100 attoMolar of pure DNA fragments from the blaCTX-M15 and floR genes, conferring resistance to b-lactams and amphenicols, respectively important for human and veterinary uses. In microbiological assays, C12a detected less than 102 CFU/mL and high concordance was observed if compared to antibiotic susceptibility tests, PCR, or to whole genome sequencing. Additionally, C12a confirmed a high prevalence of the integrase/integron system in E. coli isolates containing multiple antibiotic resistance genes (ARGs). The C12a toolbox shows equivalent detection performance in diverse laboratory settings, results redout (Fluorescence vs FLA) or input sample. Altogether, this work presents a comprehensive proof-of-concept, development description, and biochemical characterization of a collection of molecular tools to detect antibiotic resistance markers in a one health setup.
Forty papillomatous nevi, mainly with junctional nests, were partially removed surgically in such a way that a small margin was left intact on one side and the deep nevus cells were retained on the flor of the wound. After healing of the wound, a small layer of scar tissue separated the regenerated epidermis from the deep nevus cells, which were left in the dermis. After very differing intervals, as early as 30 days after the partial surgical removal, typical alterations could be observed in the epidermis above the cicatrical tissue. Most frequently, there was a hyperpigmentation with an increase in the number of basal fluorescing dendritic cells, which could also be found along the uppermost parts of epidermal appendages. Moreover, nest-like conglomerations of pigment-producing cells appeared in the form of junctional nevus cell nests. About 2-3 month after the partial surgical removal "Abtropfung" was visible, indicating a regeneration of the nevus. Fluorescence-histochemical and enzyme-histochemical results revealed that marked alterations can be found not only in the newly formed epidermis above the scar, which morphologically show minor alterations.
The electrophoretic pattern of the untreated common bean globulin cv. Flor de Mayo had 7 protein fractions ranging from 620 to 120 kilodaltons (kd). The last molecular weight corresponds to the monomeric form. One of the objectives of the present work was to establish a comparison among denaturation by heat, sodium dodecyl sulphate (SDS) and dithiothreitol (DTT). At pH 6.0, two bands were resistant to heat treatment, after SDS treatment of the untreated globulin several bands disappeared and two new bands with 26 and 15 kd appeared. DTT did not change the electrophoretic pattern, due to the small quantity of free SH groups in the globulin. At pH 6.0, phaseolin is partly resistant to heat denaturation due to aggregation in an acidic environment. Isoelectrofocusing (IEF) and SDS polyacrylamide gel electrophoresis (SDS-PAGE) separated phaseolin into 10 protein fractions. The hypothesis is that phaseolin or globulin aggregation is due to the charge difference of fractions.
This study investigated Shigella species' antibiotic resistance patterns and genomic characteristics from small ruminants and manure collected in Potchefstroom, North West, South Africa. Whole genome sequencing was used to determine resistome profiles of Shigella flexneri isolates from small ruminants' manure and Shigella boydii from sheep faeces. Comparative genomics was employed on the South African 261 S. flexneri strains available from GenBank, including the sequenced strains in this study, by investigating the serovars, antibiotic resistance genes (ARGs), and plasmid replicon types. The S. flexneri strains could not be assigned to known sequence types, suggesting novel or uncharacterized lineages. S. boydii R7-1A was assigned to sequence type 202 (ST202). Serovar 2A was the most common among South African S. flexneri strains, found in 96% of the 250 compared human-derived isolates. The shared mdf(A) was the most prevalent gene, identified in 99% of 261 S. flexneri genomes, including plasmid replicon types ColRNAI_1 (99%) and IncFII_1 (98%). Both species share a core set of resistance determinants mainly involving β-lactams (ampC1, ampC, ampH), macrolides (mphB), polymyxins (eptA, pmrF), multidrug efflux pumps (AcrAB-TolC, Mdt, Emr, Kpn families), and regulatory systems (marA, hns, crp, baeRS, evgAS, cpxA, gadX). However, S. boydii possesses additional resistance genes conferring resistance to tetracyclines (tet(A)), phenicols (floR), sulphonamides (sul2), and aminoglycosides (APH(3'')-Ib, APH(6)-Id), along with the acrEF efflux pump components (acrE, acrF). In contrast, S. flexneri harboured unique genes linked to polymyxin resistance (ugd) and regulatory functions (sdiA, gadW) that were absent in S. boydii. These findings highlight Shigella strains' genomic diversity and antimicrobial resistance potential in livestock-associated environments. Moreover, S. boydii highlights the potential risk of multidrug-resistant bacteria in farming and environmental routes. KEY POINTS: • First whole genome study of Shigella from manure and small ruminants in South Africa. • Shigella boydii strain carried multiple resistance genes to β-lactams and tetracycline. • Multidrug efflux pump gene mdf(A) was detected in 99% of South African Shigella flexneri strains.
The monophasic variant of Salmonella enterica serovar Typhimurium (STVM) represents a growing threat to global public health owing to its wide dissemination, capacity to adapt to multiple hosts, and antimicrobial resistance. In this study, 98 STVM isolates recovered in Colombia (57 from humans and 41 from pig farms and abattoirs) were genomically characterized between 2015 and 2022 and compared with 102 representative genomes of international lineages by whole-genome sequencing (WGS) and phylogenomic analysis. Phylogenomic analysis revealed the existence of two well-defined endemic lineages in Colombia (Clusters 1 and 2), arising from independent introduction events and subsequent local stabilization. Both lineages comprise isolates of human and swine origin without clear phylogenetic separation by host species, suggesting active zoonotic cocirculation and closely integrated interspecies transmission dynamics. Marked differences were observed in the accessory genome, including the differential presence of prophages (e.g., Gifsy-2, Fels-2, SW9), virulence plasmids, and resistance profiles. The Colombian lineages exhibited a high frequency of the pSTV plasmid (85%, n = 84/98) and a substantial burden of resistance determinants to quinolones (such as qnrB19, 74.5%; gyrA S83F mutation, 19.4%), phenicols (floR), tetracyclines (tetA, tetB), β-lactams (blaTEM-1B), and heavy metals. In contrast, the Colombian genomes clustered with the European ST34 lineage lacked pSTV but retained resistance and heavy metal operons. These findings demonstrate that international and endemic lineages coexist in Colombia with independent evolutionary trajectories, underscoring the need to strengthen genomic surveillance under the "One Health" approach to anticipate emerging threats and develop integrated control strategies.IMPORTANCEThe monophasic variant of Salmonella Typhimurium (STVM) has emerged as a predominant serovar in both humans and swine internationally. In Colombia, a fundamental question driving this study was whether local isolates belonged to international lineages or represented endemic strains. This study provides the first comprehensive genomic characterization demonstrating that two Colombian endemic lineages circulate simultaneously between humans and pigs without phylogenetic separation by host species, confirming active zoonotic transmission. The results demonstrate the coexistence of both lineages, each with distinctive repertoires of mobile genetic elements and specific antimicrobial resistance profiles. Understanding these transmission dynamics and evolutionary patterns is crucial for public health, as it demonstrates how zoonotic pathogens can establish locally adapted lineages with distinct resistance patterns. The genomic evidence of sustained interspecies circulation highlights the critical need for integrated surveillance strategies under the "One Health" framework. This will enable anticipating emerging threats, tracing transmission routes, and developing targeted interventions in food production systems.
The cloning of avirulence genes has greatly aided our understanding of plant-pathogen specificity. It has proven that the gene-for-gene relationship first noted by Flor is correct--single avirulence gene encoding single protein products indeed are the genetic elements that interact with plant disease resistance genes. Furthermore, firm genetic evidence has provided insight into how two cloned avirulence genes (the TMV coat gene and avrD) cause the HR. The differences in structure of pathogen elicitors also indicates that plants have evolved diverse recognitional mechanisms to detect pathogens. It is appealing to speculate, therefore, that elicitors represent the plant equivalent of antigens in vertebrates. Another consequence of these results has been the establishment of firm genetic and biochemical evidence supporting the elicitor-receptor model for recognition of incompatible pathogen races by plants. In both TMV and bacterial pathogens, we are also beginning to understand how avirulence genes are altered to confound plant recognition of the pathogen. The next few years should yield additional information on avirulence gene structure as well as the important questions of their function in the pathogen and the molecular mechanisms whereby plant recognition occurs. The marked successes in cloning avirulence genes underscore only more forcefully the pressing need to clone and characterize plant disease resistance genes. Certainly an understanding of these genes is required to further our basic knowledge of active defense in plants and to permit their manipulation for improved control of plant diseases in practical agriculture.
The effects of changes in CO2 and O2 on the mechanics of collateral ventilation were studied in anesthetized paralyzed dogs. A doublelumen catheter was wedged into a peripheral airway obstructing a segment of lung distal to the catheter. Through one lumen of the catheter, air, 5% CO2 in air, 10% CO2 in air, 5% O2 in N2, or 5% CO2 in N2 was infused at a constant flow (V). Pressure (Ps) was monitored through the other lumen. At functional residual capacity the resistance to collateral flor Rcoll = Ps/V. When V was interrrupted , the time for Ps to fall 63% was defined as the time constant for collateral ventilation, Tcoll. The effective compliance (Cs') = Tcoll/Rcoll. When air was replaced by 5% CO2, Rcoll fell 46.3% (+/- SE 2.8) and Tcoll fell 41.5% (+/- SE 3.0). When the CO2 concentration was increased from 5% to 10%, Rcoll fell an additional 9.2% (+/- SE 2.2) and Tcoll fell an additional 5.1% (+/- SE 4.4). When air was replaced by 5% O2 in N2, Rcoll rose 36.6% (+/- SE 6.0) and Tcoll rose 13.6% (+/- SE 10.5). No significant changes in Cs' were noted. We conclude that varying concentrations of CO2 and O2 provide potent mechanisms for the control of collateral ventillation which may be of importance in the regulation of ventillation perfusion relationships at the local level.
BACKGROUND: Multidrug-Resistant Organism (MDRO) refers to bacteria that are Resistant to three or more types of antibiotics in clinical use. The global health threat posed by multidrug-resistant (MDR) bacterial pathogens and their cross-species transmission necessitates rigorous Surveillance. This urgency is amplified in China where antibiotic growth promoters were widely used in animal husbandry until the 2020 implementation of Announcement No. 194 launched by Ministry of Agriculture and Rural Affairs (Announcement 194), banning non-therapeutic antibiotics in feed. This study conducted a decade long investigation on the correlation between antimicrobial resistance (AMR) phenotypes and genetic determinants in 314 Salmonella isolates collected from waterfowl across Guangdong Province, China, utilizing disk diffusion (Kirby-Bauer method) and PCR-based detection of antibiotic resistance genes (ARGs). The study period covered the antibiotic policy transition in China, specifically encompassing the pre-ban (2013-2019) and post-ban (2020-2023) phases of the nationwide prohibition on growth-promoting antimicrobials in animal feed. METHODS: Antimicrobial Susceptibility profiles against 16 agents were determined via Kirby-Bauer testing, while PCR amplification targeted 20 ARGs. Statistical analyses evaluated phenotype-genotype correlations using Pearson`s chi-square test. RESULTS: Surveillance revealed escalating resistance rates annually. Highest resistance prevalence was observed against β-lactams and amphenicols (92.25%), whereas amikacin exhibited the lowest resistance rate (9.55%). MDR prevalence reached 87.23%, with the AMP-CAZ-GEN-FFC-TET resistance profile predominating (51.6% of isolates). Genetic analysis identified 3 to 16 ARGs per isolate was harboring, with blaTEM demonstrating the highest detection frequency (90.76%). Significant phenotype-genotype correlations (p < 0.05) were observed for 13 genes: blaCTX-M, blaTEM, blaOXA, aacC2, aph(3')-I, aac(3)-IV, aadA1, qnrS, qnrA, clmA, floR, sulII, tetA. Notably, significant declines in resistance to aminoglycosides (e.g., gentamicin from 71.7 to 3.5%) and florfenicol (from 81.1 to 9.6%) were observed after China's 2019 antibiotic ban policy (p < 0.001), underscoring the impact of targeted antimicrobial stewardship in avian husbandry. CONCLUSIONS: Analysis of 314 waterfowl Salmonella strains revealed severe multidrug resistance (MDR) and diverse resistance genes (DRGs), with 13 DRGs linked to resistance. China's antibiotic ban reduced targeted resistance, but MDR persists alarmingly via acquired DRGs and adaptation. Continued enforcement may lower aminoglycoside/phenicol resistance, but β-lactam resistance will likely endure, worsened by transcontinental blaCTX-M spread. Critically, plasmid co-selection threatens to amplify MDR, demanding genomic surveillance. Mitigation requires boosting policy compliance, developing non-antibiotic therapies, mapping mutations, establishing cross-species barriers, and prioritizing One Health interventions to block resistance spread.
Companion animals can serve as reservoirs of antimicrobial resistance genes and zoonotic microorganisms, yet information on shelter dogs remains limited. This study characterized the oral microbiota and screened for antimicrobial resistance genes in shelter dogs in Japan. Oral swabs were collected from 81 dogs, microbial genomic DNA was extracted, bacterial communities were profiled by 16S rRNA gene amplicon sequencing, and antimicrobial resistance genes were screened by PCR. We detected genes conferring resistance to several antimicrobial classes, including β-lactams, tetracyclines, macrolide-lincosamide-streptogramin B, phenicols, and sulfonamides. cfxA was detected in all 81 samples, followed by sul1 (66/81), tet(M) and sul2 (65/81), floR (39/81), mecA (17/81), and erm(B) (15/81). We identified potentially pathogenic genera including Capnocytophaga, Pasteurella, Fusobacterium, Campylobacter and Corynebacterium. Microbiome analysis revealed that at the phylum level, Pseudomonadota and Bacteroidota were the most dominant, while Porphyromonas, Frederiksenia and Moraxella were the most prevalent genera. Our findings highlight that (i) the oral microbiota of shelter dogs broadly resembles that reported in companion dogs and (ii) shelter dogs represent an overlooked reservoir of clinically relevant antimicrobial resistance genes and potentially zoonotic bacteria. Therefore, it is necessary to include shelter animals in antimicrobial resistance surveillance programs to capture any potential gaps in the antimicrobial resistance prevalence in companion animals and prevent dissemination of resistant bacteria to humans following adoption of shelter dogs and cats.