Effects of Abscisic Acid on the Transfer of Sucrose From Host, Pelargonium zonale (L.) Aiton, to a Phanerogamic Parasite, Cuscuta reflexa Roxb

1992 ◽  
Vol 19 (6) ◽  
pp. 679 ◽  
Author(s):  
FD Bock ◽  
A Fer
Keyword(s):  
Abscisic Acid ◽  
Facilitated Diffusion ◽  
Pelargonium Zonale ◽  
Leaf Petiole ◽  
Cuscuta Reflexa ◽  
Host Tissues ◽  
Stem Slices ◽  
Parasitised Host

Using isolated Pelargonium leaves parasitised by Cuscuta, we have established by means of autoradiographs that, in vivo, abscisic acid (ABA) is exported from the host leaf petiole to the attached parasite shoot. Experiments with simplified models (parasitised host stem slices, unparasitised host stem slices, isolated haustoria and parasitised host stem after removal of haustoria) showed that, in vitro, [2-14C]ABA is rapidly accumulated in haustorium tissues, and the internal/external ratio of ABA becomes greater than 1 within 45 min. The very fast ABA uptake, strongly dependent on the pH, may involve facilitated diffusion in addition to the diffusion of the undissociated acid. The high level of ABA concentration in Cuscuta, especially in haustoria, might be explained by ABA import from host tissues. In Cuscuta stem and haustoria, the hormone enhances the uptake and decreases the efflux of sucrose. In host tissues, ABA enhances phloem unloading of sucrose and decreases sucrose uptake. Thus, ABA may have a central role in the host-parasite relationship by enhancing sucrose transfer.

Mechanisms of pathogenesis in Sclerotium bataticola on sunflowers. II. Pectolytic and cellulolytic enzyme production in vitro and in vivo

1970 ◽  
Vol 48 (6) ◽  
pp. 1073-1077 ◽  
Author(s):  
Yu-Ho Chan ◽  
W. E. Sackston
Keyword(s):  
Enzyme Production ◽  
Pectin Methylesterase ◽  
Cellulolytic Enzyme ◽  
Culture Filtrates ◽  
Healthy Control ◽  
Host Tissues

Pectin methylesterase (PME), endopolygalacturonase (Endo-PG), exopolygalacturonase (Exo-PG), pectin trans-eliminase (PTE), polygalacturonase trans-eliminase (PGTE), cellulase, and cellobiase activities were investigated in culture filtrates of Sclerotium bataticola, and in extracts of inoculated and uninoculated sunflower stems. All of the enzymes except PTE were produced in culture filtrates of the pathogen and in diseased host tissues. Only PME was detected in healthy control plants.

In vitro and in vivo interactions between Erwinia amylovora and related saprophytic bacteria

1975 ◽  
Vol 21 (1) ◽  
pp. 35-41 ◽  
Author(s):  
J. M. Erskine ◽  
L. E. Lopatecki
Keyword(s):  
Erwinia Amylovora ◽  
Virulent Strain ◽  
Sucrose Concentration ◽  
Sugar Content ◽  
Susceptible Host ◽  
The Status ◽  
Highly Virulent ◽  
Host Tissues

Under carefully controlled laboratory conditions, a highly virulent strain of Erwinia amylovora coinhabited susceptible host tissues with a yellow saprophytic bacterium, which was invariably isolated from fire blight infected trees, with or without producing symptoms of the disease depending on the status of a number of environmental factors, both climatic and physiological. In particular, variation of temperature and sucrose concentration determined, independently, the equilibrium of a readily reversible alternation of predominance of the two bacteria.It is suggested that E. amylovora may sometimes exist as an avirulent resident on the surface or within healthy host plants when environmental conditions favor growth of the yellow saprophyte rather than the pathogen. Such conditions, which are more likely to be obtained in midsummer and the fall, include temperature fall or rise below or above the optimum for E. amylovora, decreased humidity or diminution of sap flow, and increased sugar content in the host tissues.

scholarly journals Streptococcus Adherence and Colonization

2009 ◽  
Vol 73 (3) ◽  
pp. 407-450 ◽  
Author(s):  
Angela H. Nobbs ◽  
Richard J. Lamont ◽  
Howard F. Jenkinson
Keyword(s):  
Cell Wall ◽  
Molecular Techniques ◽  
Host Cells ◽  
In Vivo Studies ◽  
Regulatory Pathways ◽  
Mucosal Tissues ◽  
Extracellular Matrix Components ◽  
Host Tissues

SUMMARY Streptococci readily colonize mucosal tissues in the nasopharynx; the respiratory, gastrointestinal, and genitourinary tracts; and the skin. Each ecological niche presents a series of challenges to successful colonization with which streptococci have to contend. Some species exist in equilibrium with their host, neither stimulating nor submitting to immune defenses mounted against them. Most are either opportunistic or true pathogens responsible for diseases such as pharyngitis, tooth decay, necrotizing fasciitis, infective endocarditis, and meningitis. Part of the success of streptococci as colonizers is attributable to the spectrum of proteins expressed on their surfaces. Adhesins enable interactions with salivary, serum, and extracellular matrix components; host cells; and other microbes. This is the essential first step to colonization, the development of complex communities, and possible invasion of host tissues. The majority of streptococcal adhesins are anchored to the cell wall via a C-terminal LPxTz motif. Other proteins may be surface anchored through N-terminal lipid modifications, while the mechanism of cell wall associations for others remains unclear. Collectively, these surface-bound proteins provide Streptococcus species with a “coat of many colors,” enabling multiple intimate contacts and interplays between the bacterial cell and the host. In vitro and in vivo studies have demonstrated direct roles for many streptococcal adhesins as colonization or virulence factors, making them attractive targets for therapeutic and preventive strategies against streptococcal infections. There is, therefore, much focus on applying increasingly advanced molecular techniques to determine the precise structures and functions of these proteins, and their regulatory pathways, so that more targeted approaches can be developed.

scholarly journals Ciprofloxacin-Loaded Gold Nanoparticles against Antimicrobial Resistance: An In Vivo Assessment

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3152
Author(s):  
Afrah Nawaz ◽  
Syed Mohsin Ali ◽  
Nosheen Fatima Rana ◽  
Tahreem Tanweer ◽  
Amna Batool ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Metallic Nanoparticles ◽  
Beta Lactams ◽  
In Vitro Antibacterial Activity ◽  
Bacteria Resistance ◽  
Host Tissues ◽  
In Vivo Assessment

Metallic nanoparticles, such as gold nanoparticles (AuNPs), have been extensively studied as drug delivery systems for various therapeutic applications. However, drug-loaded-AuNPs have been rarely explored in vivo for their effect on bacteria residing inside tissues. Ciprofloxacin (CIP) is a second-generation fluoroquinolone with a broad-spectrum of antibiotic properties devoid of developing bacteria resistance. This research is focused on the synthesis and physical characterization of Ciprofloxacin-loaded gold nanoparticles (CIP-AuNPs) and their effect on the colonization of Enterococcus faecalis in the liver and kidneys of mice. The successfully prepared CIP-AuNPs were stable and exerted enhanced in vitro antibacterial activity against E. faecalis compared with free CIP. The optimized CIP-AuNPs were administered (500 µg/Kg) once a day via tail vein to infected mice for eight days and were found to be effective in eradicating E. faecalis from the host tissues. Moreover, unlike CIP, CIP-AuNPs were non-hemolytic. In summary, this study demonstrated that CIP-AuNPs are promising and biocompatible alternative therapeutics for E.-faecalis-induced infections resistant to conventional drugs (e.g., beta-lactams and vancomycin) and should be further investigated.

scholarly journals The effects of oestradiol on nucleoside transport in rat uterus

1971 ◽  
Vol 121 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Janet M. Oliver
Keyword(s):  
Cytosine Arabinoside ◽  
Concentration Gradient ◽  
Initial Rate ◽  
Nucleoside Transport ◽  
Facilitated Diffusion ◽  
Rat Uterus ◽  
Intracellular Space ◽  
Uridine Uptake

1. By using the non-metabolized cytidine analogue, cytosine arabinoside, it was possible to examine the mechanism of nucleoside transport in the immature rat uterus in the absence of intracellular utilization of the permeant. It was demonstrated that the uptake of cytosine arabinoside is not accumulative and that it can be competitively inhibited by the addition of a second nucleoside, uridine. Introduction of a concentration gradient of uridine from the medium towards the intracellular water promotes the counterflow of cytosine arabinoside out of the cells against its concentration gradient. These properties indicate that a facilitated-diffusion system is involved in nucleoside transport in the uterus. Further counterflow studies have shown that the transport system has a broad specificity for purine and pyrimidine nucleosides and that it is distinct from the processes that mediate the uptake of sugars, amino acids and purine and pyrimidine bases. 2. Oestradiol injection has no effect on the initial rate of cytosine arabinoside uptake in vitro. The increased amount of the analogue taken up per uterus is simply due to the expansion of the uterine volume that accompanies oestrogen action. 3. It is concluded that the striking increase in uridine uptake, observed in vivo in uteri from oestrogen-treated rats, does not result from an increase in the initial rate of nucleoside transport into the intracellular space of the tissue.

Abscisic Acid and Sucrose Control of Velvetleaf (Abutilon theophrasti) Ovule Development in Vitro

Weed Science ◽  
1984 ◽  
Vol 32 (6) ◽  
pp. 798-801 ◽  
Author(s):  
Laura K. Thompson ◽  
Gerald R. Leather ◽  
Maynard G. Hale
Keyword(s):  
Abscisic Acid ◽  
Embryo Development ◽  
Parental Control ◽  
Abutilon Theophrasti ◽  
Ovule Development ◽  
Precocious Germination ◽  
Development In Vitro ◽  
Days After Anthesis

The culture of ovules excised from velvetleaf (Abutilon theophrasti Medic., ♯4 ABUTH) capsules 5 days after anthesis was used to measure the effects of abscisic acid (ABA) and sucrose on embryo development and prevention of precocious germination. ABA at 1 × 10-7 M combined with 6% sucrose in the medium for the first 14 days of culture increased embryo development but prevented precocious germination. Higher concentrations of ABA inhibited embryo development. Without ABA, precocious germination increased directly with the concentration of sucrose in the medium, and embryos died. In vivo, ABA reached its highest concentration in ovules 5 days after anthesis but was undetectable after 16 days. Parental control of embryo development may involve ABA and an increasing concentration of osmoticum as seeds dehydrate during maturation.

scholarly journals Virulence ofStaphylococcus epidermidisin a mouse model: significance of extracellular slime

1996 ◽  
Vol 117 (2) ◽  
pp. 267-280 ◽  
Author(s):  
M. A. Deighton ◽  
R. Borland ◽  
J. A. Capstick
Keyword(s):  
Mouse Model ◽  
Extracellular Polysaccharide ◽  
Solid Surfaces ◽  
Chronic Infections ◽  
Large Numbers ◽  
Implanted Device ◽  
Host Tissues ◽  
Extracellular Slime

SummaryThe ability to produce large quantities of bioflim on solid surfacesin vitrois believed to distinguish potentially pathogenic strains ofStaphylococcus epidermidisfrom commensals. Bioflim consists of staphylococcal cells encased in a matrix of extracellular polysaccharide (also referred to as slime), firmly adherent to each other and to the underlying surface structure. The association of slime with colonization of catheter surfacesin vivohas been examined extensively. Less attention has been paid to the contribution of slime to infections that occur in the absence of an inserted device. In a mouse model of subcutaneous infection without an implanted device 10S. epidermidisstrains (5 slime-positive, 5 slime-negative) produced abscesses; thus a foreign body is not essential for the expression of virulence byS. epidermidis. Biofilm-positive strains produced significantly more abscesses, that persisted longer than biofilm-negative strains. In these chronic infections, large numbers of staphylococci were associated with macrophages and viable staphylococci were cultured from specimens of pus collected at autopsy. Thus slime or components of slime appear to delay the clearance ofS. epidermidisfrom host tissues, possibly by interfering with intracellular killing mechanisms. However, differences in the capacity to produce abscesses, within both the slime-positive and slime-negative groups, indicate that other factors also contribute to the virulence ofS. epidermidis.

Abscisic acid enhances glucose disposal and induces brown fat activity in adipocytes in vitro and in vivo

2017 ◽  
Vol 1862 (2) ◽  
pp. 131-144 ◽  
Author(s):  
Laura Sturla ◽  
Elena Mannino ◽  
Sonia Scarfì ◽  
Santina Bruzzone ◽  
Mirko Magnone ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Brown Fat ◽  
Glucose Disposal
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