Weak Pigmentation Research Articles

The influence of selection of sires according to the degree of plumage pigmentation on the autosexness of guinea fowl

The studies were carried out on cream and silver guinea fowl populations at Genefond LLC, Moscow region. The purpose of the work was to study the effect of selecting sires with contrasting down pigmentation on the accuracy of sexing guinea fowl offspring. The basis for the creation of an autosex maternal form was cream and silver guinea fowl, carriers of the silver “S” and golden “s” genes, which in preliminary experiments showed the possibility of sexing them according to the degree of plumage pigmentation. To conduct the study, two groups of guinea fowl with cream and silver colored plumage were recruited at 20 weeks of age. In each group there were 6 selection nests; males with weak pigmentation and females with strong plumage pigmentation were taken into the nest. The ratio of males to females in the nest was 1:6. Experiments have shown the absence of significant differences between cream and silver guinea fowl populations in quantitative and qualitative indicators of sperm production, fertilization and egg hatchability. The selection of producers when recruiting a breeding herd with a contrasting plumage color (males with weak, females with strong plumage pigmentation) ensured an increase in the accuracy of sexing cream guinea fowl by 5.1%, silver guinea fowl by 1.8%, while the number of nests with sexing accuracy was more than 95 %, for cream guinea fowl it was 50%, for silver guinea fowl 66.7%, respectively.

A new Copelatus with small eyes from the Eastern Cape Wild Coast, South Africa (Coleoptera: Dytiscidae)

A new diving beetle, Copelatus mkambati sp. nov., is described from the Mkambati Nature Reserve in the Eastern Cape Province, South Africa. The new species is compared with other Afrotropical taxa with two elytral striae and no submarginal stria (the macellus species group of Copelatus Erichson, 1832). A combination of small eyes, rather weak pigmentation, flattened, subparallel habitus, relatively large head and collecting circumstances all suggest that the new species may be semisubterranean in lifestyle.

Screening for urinary tract infection-causing Klebsiella pneumoniae using CHROMagar

Introduction. Urinary tract infections (UTIs) are considered prevalent among humans. While Klebsiella pneumoniae and Escherichia coli are commonly isolated from patients with UTIs, K. pneumoniae is more frequently isolated from specimens isolated from hospital-acquired infections. Aim. The current study aimed to characterise and evaluate pathogenic K. pneumoniae isolated from patients suspected with a UTI at King Abdulaziz University Hospital. Methodology. Twenty-four urine samples obtained from patients, between 12 November 2018 and 11 January 2019, were included in the study, and the microbial content was analysed via urine culture and VITEK 2 analyses. Results. Of the 24 urine specimens, 23 samples (95.8%) yielded significant microbial growth (> 105 CFU/mL K. pneumoniae), and one sample (4.2%) yielded non-pathogenic microbial growth (< 105 CFU/mL K. pneumoniae). Of the specimens with cell counts of >105 CFU/mL, 21 samples (87.5%) were pure cultures showing the growth of a single pathogen, and three samples (12.5%) were mixed cultures, showing the growth of two or more pathogens; 10 (41.7%) samples were extended-spectrum beta-lactamase (ESBL) producers. VITEK 2 analysis showed that the most effective antibiotic was piperacillin, with 87.5% of the strains isolated in this study showing sensitivity to it, followed by gentamicin (83.3%) and ciprofloxacin (79.2%). Antibiotic susceptibility studies identified resistance against ampicillin (45.83%), trimethoprim (41.67%), and amoxicillin (25%) in the study isolates. Differential chromogenic culture media CHROMagar ESBL and CHROMagar KPC (K. pneumoniae carbapenemase) were used for rapid screening of ESBL and KPC producers. Among the 24 K. pneumoniae isolates, six isolates (25%) formed metallic blue colonies on CHROMagar ESBL, five (20.3%) were inhibited, and nine (37.5%) showed weak pigmentation. Three isolates (12.5%) formed pink colonies on CHROMagar ESBL. Seventeen isolates (70.8%) were KPC-positive, four (16.7%) showed weak pigmentation, and three (12.5%) formed pink colonies on CHROMagar KPC. The results from CHROMagar cultures agreed with those of VITEK 2 analyses. Conclusion. Various microbial detection methods have been used in medical microbiology laboratories to identify and screen for microbial resistance in clinical specimens. VITEK 2 and CHROMagar are amongst the commonly used methods. Here, we report a possible discrepancy between the detection techniques and that the data obtained by different methods need not be synergistic. However, the use of a chromogenic medium offers a quick and accurate method for detection, enumeration, and presumptive identification of urinary tract pathogens.

A new genus of cave spider from Neotropical region (Gnaphosidae: Prodidominae).

A new monotypic genus of Prodidominae, Indiani gen. nov., is proposed to include one cave species collected in limestone caves from Minas Gerais, Brazil: Indiani gaspar sp. nov. (♂♀). Based on a recent phylogenetic analysis of Prodidominae, the new genus is closely to other Neotropical Prodidominae, such as Lygromma, Brasilomma and Moreno by sharing a classic claw tuft clasper. Indiani gen. nov. is characterized by a ventral parallel rows of strong spines on tibia and metatarsus I-II, male palp with sclerotized conductor and the robust median apophysis is curved retrolaterally; the female epigyne has an anterior atrium and a posterior extension of the epigynal plate. As other cave Prodidominae, Indiani gen. nov. has morphological characteristics, such as loss or reduction of eyes and weak pigmentation, that indicate an adaptation for living in subterranean environments.

Fungal Succession During the Decomposition of Ectomycorrhizal Fine Roots.

Ectomycorrhizal (ECM) fine roots account for a substantial proportion of forest production and their decomposition releases large amounts of nutrients to the soil ecosystem. However, little is known about the fungi involved in ECM decomposition, including assemblages of fungal saprotrophs, endophytes, and the ECM fungi themselves. To follow fungal succession during the degradation of senescing fine roots, understory seedlings of Abies balsamea and Picea rubens at two sites in the Acadian forest of Nova Scotia were either severed at the root collar or left as controls. Root systems were collected sequentially over two growing seasons and assessed for fine root loss and ECM mantle integrity. ECM were identified by ITS-PCR and grouped into broad morphological categories. Fungal communities colonizing the senescing fine roots were also monitored by systematically constructing clone libraries over the course of the experiment. ECM with cottony, weakly pigmented mantles (e.g., Cortinarius) degraded within the first year. Those with cottony, but intensely pigmented mantles (Piloderma), and smooth mantles with weak pigmentation (Russulaceae) degraded more slowly. Smooth, melanized ECM (Cenococcum and Tomentella) generally maintained integrity over the course of the experiment. Rates of fine root loss and changes in ECM mantle integrity were positively correlated with soil temperature. ECM DNA was detected throughout the experiment, and was not replaced by that of saprotrophic species during the two seasons sampled. However, fungal root endophytes (e.g., Helotiaceae) initially increased in abundance and then decreased as mantles degraded, suggesting a possible role in ECM decomposition.

The Embryotoxicity of Some Phenol Derivatives on Zebrafish, Danio rerio

The existence of toxicants in ecosystems has been increased dramatically in recent years, especially in aquatic environments. Phenols and chlorinated phenol derivatives are toxic industrial compounds. Phenols and derivatives are known to be environmental contaminants. In the present study, 2,4-Dichlorophenol, 2-Chlorophenol and substituted phenol were tested for embryotoxicity and mortality in a four-day period using zebrafish, Danio rerio embryos. Tested phenol derivatives caused teratogenicity and embryo mortality in the embryos. The semi static 48-h LC50 (median lethal concentration) value for Substituted-phenol was 13.850 mg L-1; the corresponding values for 2-Chlorophenol and 2,4-Dichlorophenol were 8.378 mg L-1 and 6.558 mg L-1, respectively. The endpoints are incomplete eyes, head and tail, heart and chorda deformity, yolk sac edema, tail curvature, shrunken eyes, lordosis, delayed hatching, weak pigmentation, heart edema and non-pigmentation after exposure to the compounds. 2,4-Dichlorophenol was found to be more toxic than the others. This paper is the first to describe the relative toxicity of a suite of phenols in the early life stages of zebrafish.

Embryotoxicity and Biotransformation Responses in Zebrafish Exposed to Water-Soluble Fraction of Crude Oil

The toxic effects of water-soluble fraction (WSF) of crude oil (API27, Petrobras Campos Basin, Brazil) were evaluated during the early life stages of zebrafish, as well as its biotransformation in juvenile fish. Embryonic development was studied during 96h. Reduced heartbeat rate, weak pigmentation, tail defects, and embryo mortality were observed for all of the tested concentrations of the WSF. Activities of the biotransformation enzymes were induced at the highest concentrations, showing that these enzymes played a role in its elimination. As shown in this study the crude oil WSF altered the normal embryonic development of fish.

Comparative embryotoxicity and proteotoxicity of three carrier solvents to zebrafish ( Danio rerio) embryos

The present study examines the effects of ethanol (ETOH), dimethyl sulfoxide (DMSO), and acetone on zebrafish embryos and the implications of the observed results on the use of these solvents to zebrafish early life stage tests. The embryos were exposed to different concentrations (0.0, 0.0001, 0.001, 0.01, 0.1, 0.05, 1, 1.5, and 2.0% v/v) of the respective solvents by diluting reagent-grade solvent with reconstituted water [DIN 38415-6—Suborganismische Testverfahren (Gruppe T) Teil 6: Giftigkeit gegenüber Fischen. Deutsches Institute für Normung e.V]. The following endpoints were investigated (mortality, hatching rate, abnormalities, heart rate, and hsp 70 induction). No effect on survival was recorded for both acetone and DMSO even up to the highest concentration. On the other hand, embryos exposed to 1.5% and 2.0% ethanol showed a significant reduction in survival rate. No developmental defects occurred with any of the solvents at the 0.1% concentration. However, starting with 1.0%, weak to very pronounced abnormalities (weak pigmentation, edema, crooked bodies, eye defect, tail defect, reduced heartbeat, and abnormal hatching) were observed depending on the solvent type and the concentration used. Ethanol has been shown to be the most embryotoxic solvent while DMSO and acetone have comparably lesser effects. Heat shock protein 70 was induced by all solvents but at different concentration ranges. DMSO has been shown to be the most potent inducer of stress proteins. Based on the study, the chemicals tested here may be used as carrier solvents in the zebrafish embryo assay at levels below 1.5, 1.5, and 1% v/v for acetone, DMSO, and ethanol, respectively. For stress protein analysis of the exposed embryos, however, the solvent levels should be below 0.1%, 0.01%, and 1.5%, respectively. Additional and separate investigations utilizing other biomarkers should be carried out to further validate the suitability of using these solvents in a typical zebrafish embryo assay.

Characterization of Greek populations of faba bean (Vicia faba L.) and their evaluation using a new parameter

Using data from four environments of a two-year experiment, a collection of 55 Greek faba bean populations wascharacterized on the basis of ten morphological and ten agronomical traits. The collection can be described ashaving flowers with medium intensity of streaks on standard petal, two to three flowers per inflorescence, leaveswith six leaflets per leaf, sub-elliptic leaflet shape and small or medium leaflet size. The stems had weak ormedium pigmentation at flowering time, were of low or medium thickness, had medium height and mediumbranching from basal nodes and high resistance to lodging. Pods were mainly basal with pendent attitude, flattenedin shape, had dark colour at maturity and were small with few ovules and seeds. Most seeds had testa of light greencolour. This characterization makes the present collection similar to other South European faba bean populations.Apart from characterization, collections should also be evaluated from the breeding point of view. Since themost desirable populations within a collection are those with valuable but 'low frequency' levels of traits, theparameter R (rareness) was proposed. For each trait, a partial rareness (R ) parameter is calculated using only ithose trait levels that can be considered as having 'low frequency'. The parameter R is the sum of the 'partialrarenesses'. Populations with high frequencies of the 'lowest frequency' levels of traits in the collection arecharacterized by high values of R and can, therefore, be more easily identified.

Nesticella marapu sp. n., a blind nesticid (Araneae: Nesticidae) from Sumba, Indonesia

A new species of the genus Nestacella is described from both sexes. It is characterised by the presence of a beak-shaped paracymbium. It has long legs and weak pigmentation but lacks eyes.

Endogenous and environmental factors influence 35S promoter methylation of a maize A1 gene construct in transgenic petunia and its colour phenotype.

30,000 transgenic petunia plants carrying a single copy of the maize A1 gene, encoding a dihydroflavonol reductase, which confers a salmon red flower colour phenotype on the petunia plant, were grown in a field test. During the growing season plants with flowers deviating from this salmon red colour, such as those showing white or variegated phenotypes and plants with flowers exhibiting only weak pigmentation were observed with varying frequencies. While four white flowering plants were shown at the molecular level to be mutants in which part of the A1 gene had been deleted, other white flowering plants, as well as 13 representative plants tested out of a total of 57 variegated individuals were not mutants but rather showed hypermethylation of the 35S promoter directing A1 gene expression. This was in contrast to the homogeneous fully red flowering plants in which no methylation of the 35S promoter was observed. While blossoms on plants flowering early in the season were predominantly red, later flowers on the same plants showed weaker coloration. Once again the reduction of the A1-specific phenotype correlated with the methylation of the 35S promoter. This variation in coloration seems to be dependent not only on exogenous but also on endogenous factors such as the age of the parental plant from which the seed was derived or the time at which crosses were made.

Antibiotic Resistance Patterns and Pigment Production of Streptococci of Serological Group B Isolated from Bovines and Humans

All 127 streptococci of serological group B isolated from bovines and humans were resistant to bacitracin (0.04 U) and gentamicin and susceptible to penicillin. Of the bovine isolates examined 10%, 8%, 22%, 2% and 30% were resistant to bacitracin (10 U), cefoxitin, clindamycin, erythromycin and tetracycline respectively. Of the human isolates 52%, 21%, 38%, 3% and 65% were resistant to bacitracin (10 U), cefoxitin, clindamycin, erythromycin and tetracycline respectively. Most of the bovine strains were susceptible, most of the human strains were resistant to bacitracin and tetracycline. A relation of tetracycline resistance to group B streptococcal microcapsule was proposed. Pigmentation studies revealed generally a weak pigmentation of bovine and a strong pigmentation of human group B streptococci. Antibiotic resistance patterns together with the ability to form a yellow to orange-red pigment might be used for characterization of individual cultures of group B streptococci.

Study of intralocus events leading to R stippled (R st) recombinants in Zea mays

The two main components of the R locus, designated P and S condition the production of a red pigment, chemically identifiable with cyanidin 3-glucoside, in the plant and seed tissues respectively. In this paper we present some data on the structural organization in terms of its P and S components of an unstable form of R, designated R st, and of two of its derivatives. The superscript st (stippled) refers to a distinctive pattern of aleurone variegation conditioned by R st. The instability is seemingly the result of the interaction of the S component of R st with an adjacent element affecting its gene action. The two stippled derivatives analyzed are R sk (smoky) that conditions a different pattern of aleurone variegation and R sc (self-colored) characterized by a homogeneous aleurone pigmentation. Assuming that R st is a gene complex, p S st in structure, heterozygous P s / p S st individuals should yield P S st and p s recombinants, besides the parental P s and p S st strands. Accordingly Ps / p S st male parents, carrying appropriate outside markers, were crossed with a p s / p s line. Among the progeny of this cross the exceptional individuals carrying nonparental strands were isolated as presumed intralocus recombinants and their flanking markers constitution was established. This analysis, extended to the p S sk and p S sc complex shows: The possible origin of the nonparental strands through a mechanism of gene conversion or chromosomal deletion is considered and the evidence in favour or against either hypothesis is discussed. The occurrence of P S st strands offers the opportunity to analyze the effect of S st on P gene action. This test was performed by comparing the pigment concentration and distribution of individuals genotypically P S st/p s and p S st / P s. The comparison shows that seedlings of the two genotypes differ significantly both in the amount of pigment produced and its distribution. While the former determines a weak pigmentation, phenotypically recognisable as sectors or fine stripes along the primary root, the latter shows a homogencous pigmentation amounting to six times that found in P S st seedlings. These observations seem to indicate that both P and S, when lying in coupling on the same chromosome together with the instability factor, are coordingted in their action by the latter.