The importance of refuge habitat in the local conservation of stripe-faced dunnarts Sminthopsis macroura on arid rangelands.

2005 ◽  
Vol 27 (1) ◽  
pp. 75 ◽  
Author(s):  
A Frank ◽  
T Soderquist
Keyword(s):  
Arid Regions ◽  
Arid Zone ◽  
Critical Role ◽  
Domestic Sheep ◽  
Anthropogenic Change ◽  
Local Conservation ◽  
European Settlement ◽  
Naturally Occurring ◽  
Sminthopsis Macroura ◽  
Arid Rangelands

ANTHROPOGENIC change to Australian habitats accelerated rapidly during the late 1800s as sheep grazing spread across the continent. In particular, intensive grazing in arid and semi-arid regions is believed to have vastly altered vegetation communities, triggered extensive soil erosion, and reduced shelter available to small mammals, thus increasing their vulnerability to predation (Morton 1990). It is not surprising, then, that since European settlement 32 species (42%) of mammals inhabiting the arid zone of Australia have become extinct (Landsberg et al. 1997), and many others have suffered major range reductions or are currently considered widespread but rare. This faunal collapse was due to multiple factors (Burbidge and McKenzie 1989; Morton 1990), but the most consistent predictor of marsupial decline is geographic overlap with domestic sheep (Fisher et al. 2003). While overgrazing is a serious broadscale problem, the destruction of naturally occurring pockets of highquality habitat probably played a critical role in the extirpation of species that relied on refugia for survival during droughts (Morton 1990).

scholarly journals Aspects of the ecophysiology and the dietary strategy of the greater bilby Macrotis lagotis: a review.

2004 ◽  
Vol 26 (2) ◽  
pp. 179 ◽  
Author(s):  
LA Gibson ◽  
ID Hume
Keyword(s):  
Nutritional Value ◽  
Arid Regions ◽  
Food Source ◽  
Arid Zone ◽  
Feeding Strategy ◽  
Separation Mechanism ◽  
European Settlement ◽  
In Captivity ◽  
Dietary Strategy ◽  
The Arid Regions

Since European settlement, the distribution of the greater bilby (Macrotis lagotis), an omnivorous peramelid marsupial, has contracted into the driest and least fertile parts of its former range. A review of the dietary, metabolic and digestive strategies used by M. lagotis provides the basis for an explanation of its ability to persist in the arid regions where it is now restricted. M. lagotis utilises an opportunistic feeding strategy, selecting dietary items in accordance with their abundance. Termites, ants and seeds, that form a concentrated food source, are prevalent in their diet. In captivity, M. lagotis exhibits a flexible digestive strategy that enables them to use diets of varying nutritional value. However, the absence of a colonic separation mechanism in the hindgut suggests that they are limited to relatively low-fibre diets, and this is reflected in their diet in the field. The low water and maintenance nitrogen requirements of M. lagotis are consistent with arid habitation, but the field metabolic rate is higher than expected for an arid-zone mammal, which suggests that water rather than energy conservation is a priority for this species.

scholarly journals Contribution of Target Gene Mutations and Efflux to Decreased Susceptibility of Salmonella enterica Serovar Typhimurium to Fluoroquinolones and Other Antimicrobials

2006 ◽  
Vol 51 (2) ◽  
pp. 535-542 ◽  
Author(s):  
Sheng Chen ◽  
Shenghui Cui ◽  
Patrick F. McDermott ◽  
Shaohua Zhao ◽  
David G. White ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Efflux Pump ◽  
Critical Role ◽  
Gene Mutations ◽  
Efflux Pumps ◽  
Fluoroquinolone Resistance ◽  
Naturally Occurring ◽  
Serovar Typhimurium ◽  
Resistant Mutants ◽  
Increased Susceptibility

ABSTRACT The mechanisms involved in fluoroquinolone resistance in Salmonella enterica include target alterations and overexpression of efflux pumps. The present study evaluated the role of known and putative multidrug resistance efflux pumps and mutations in topoisomerase genes among laboratory-selected and naturally occurring fluoroquinolone-resistant Salmonella enterica serovar Typhimurium strains. Strains with ciprofloxacin MICs of 0.25, 4, 32, and 256 μg/ml were derived in vitro using serovar Typhimurium S21. These mutants also showed decreased susceptibility or resistance to many nonfluoroquinolone antimicrobials, including tetracycline, chloramphenicol, and several β-lactams. The expression of efflux pump genes acrA, acrB, acrE, acrF, emrB, emrD, and mdlB were substantially increased (≥2-fold) among the fluoroquinolone-resistant mutants. Increased expression was also observed, but to a lesser extent, with three other putative efflux pumps: mdtB (yegN), mdtC (yegO), and emrA among mutants with ciprofloxacin MICs of ≥32 μg/ml. Deletion of acrAB or tolC in S21 and its fluoroquinolone-resistant mutants resulted in increased susceptibility to fluoroquinolones and other tested antimicrobials. In naturally occurring fluoroquinolone-resistant serovar Typhimurium strains, deletion of acrAB or tolC increased fluoroquinolone susceptibility 4-fold, whereas replacement of gyrA double mutations (S83F D87N) with wild-type gyrA increased susceptibility >500-fold. These results indicate that a combination of topoisomerase gene mutations, as well as enhanced antimicrobial efflux, plays a critical role in the development of fluoroquinolone resistance in both laboratory-derived and naturally occurring quinolone-resistant serovar Typhimurium strains.

scholarly journals The Naturally Occurring Mutants of DDB Are Impaired in Stimulating Nuclear Import of the p125 Subunit and E2F1-Activated Transcription

1999 ◽  
Vol 19 (7) ◽  
pp. 4935-4943 ◽  
Author(s):  
Pavel Shiyanov ◽  
Steven A. Hayes ◽  
Manjula Donepudi ◽  
Anne F. Nichols ◽  
Stuart Linn ◽  
...  
Keyword(s):  
Dna Binding ◽  
Critical Role ◽  
Binding Activity ◽  
Single Amino Acid ◽  
Nuclear Accumulation ◽  
Stable Complex ◽  
Deficiency Disease ◽  
Naturally Occurring ◽  
Repair Deficiency ◽  
Damaged Dna

ABSTRACT The human UV-damaged-DNA binding protein DDB has been linked to the repair deficiency disease xeroderma pigmentosum group E (XP-E), because a subset of XP-E patients lack the damaged-DNA binding function of DDB. Moreover, the microinjection of purified DDB complements the repair deficiency in XP-E cells lacking DDB. Two naturally occurring XP-E mutations of DDB, 82TO and 2RO, have been characterized. They have single amino acid substitutions (K244E and R273H) within the WD motif of the p48 subunit of DDB, and the mutated proteins lack the damaged-DNA binding activity. In this report, we describe a new function of the p48 subunit of DDB, which reveals additional defects in the function of the XP-E mutants. We show that when the subunits of DDB were expressed individually, p48 localized in the nucleus and p125 localized in the cytoplasm. The coexpression of p125 with p48 resulted in an increased accumulation of p125 in the nucleus, indicating that p48 plays a critical role in the nuclear localization of p125. The mutant forms of p48, 2RO and 82TO, are deficient in stimulating the nuclear accumulation of the p125 subunit of DDB. In addition, the mutant 2RO fails to form a stable complex with the p125 subunit of DDB. Our previous studies indicated that DDB can associate with the transcription factor E2F1 and can function as a transcriptional partner of E2F1. Here we show that the two mutants, while they associate with E2F1 as efficiently as wild-type p48, are severely impaired in stimulating E2F1-activated transcription. This is consistent with our observation that both subunits of DDB are required to stimulate E2F1-activated transcription. The results provide insights into the functions of the subunits of DDB and suggest a possible link between the role of DDB in E2F1-activated transcription and the repair deficiency disease XP-E.

Diversity and distribution of the orthopteroid insects of the Galápagos Islands, Ecuador

1996 ◽  
Vol 74 (8) ◽  
pp. 1497-1510 ◽  
Author(s):  
Stewart B. Peck
Keyword(s):  
Species Richness ◽  
Introduced Species ◽  
Arid Zone ◽  
Galapagos Islands ◽  
Galápagos Islands ◽  
Surface Transport ◽  
Naturally Occurring ◽  
Ecological Complexity ◽  
Tropical America ◽  
Orthopteroid Insects

New fieldwork has brought the entire "orthopteroid" fauna of the Galápagos Islands to a total of 57 species, in 37 genera, and 7 insect orders. Identification keys and distributional details are given for the 24 species in the order Orthoptera (s.str.) (Ensifera and Caelifera). Of these, 19 species (and 2 genera) are endemic, 2 species are native (naturally occurring elsewhere in tropical America), and 3 species are presumed to have been introduced by humans. It is assumed that ancestral natural colonizations occurred through the air by flying ancestors or through rafting and ocean-surface transport by flightless ancestors (in Gryllidae; Nemobiinae and Mogoplistinae). Of the indigenous (non-introduced) species, 71% of Orthoptera (s.str.) and 72% of all orthopteroids of the Galápagos Islands are now flightless in one or both sexes. Considering the richness of the total orthopteroid fauna in mainland Ecuador, the island fauna is very highly impoverished. Evolution and diversification are modest in the Galápagos orthopteroids compared with some other plants and animals. Some species (probably descendant from coastal arid zone ancestors) are now limited to either moist highland or cave habitats. Species richness is significantly positively correlated with island ecological complexity and island area.

Naturally occurring hypertension in New World nonhuman primates: potential role of the perifornical hypothalamus

2007 ◽  
Vol 292 (2) ◽  
pp. R937-R945 ◽  
Author(s):  
Orville A. Smith ◽  
Cliff A. Astley
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
New World ◽  
Critical Role ◽  
Cardiovascular Responses ◽  
Routine Laboratory ◽  
New World Primates ◽  
Naturally Occurring

Hypertension is a prominent underlying factor in the genesis of cardiovascular-related morbidity and mortality. A major impediment to the investigation into the causes of the disease is the paucity of naturally occurring animal models of the disease. There is evidence that some species of New World primates spontaneously become hypertensive. We used chronically implanted pressure transducers to assess normally occurring blood pressure and heart rate levels at rest and during routine laboratory procedures in a group of one of these New World primates ( Aotus sp.). Resting mean arterial pressure ranged from 72 to 130 mmHg. Three animals were judged to have resting mean arterial pressure levels in the hypertensive range (≥110 mmHg). In all of the animals, pressor responses to routine laboratory events were exaggerated (average highest mean pressure during 1 min from any session was 97–196 mmHg). Subsequently, the region of the perifornical/lateral hypothalamus known to produce elevated blood pressure and heart rate responses to electrical stimulation was removed, and the blood pressure responses to the laboratory routines were significantly decreased and, in some cases, eliminated. Control lesions in nearby tissue had no effect on these responses. This region may play a critical role in initiating or exacerbating cardiovascular responses that contribute to the development of essential hypertension.

The decline of the Brushtail Possum, Trichosurus vulpecula (Kerr 1798), in arid Australia.

1992 ◽  
Vol 14 (2) ◽  
pp. 107 ◽  
Author(s):  
JA Kerle ◽  
JN Foulkes ◽  
RG Kimber ◽  
D Papenfus
Keyword(s):  
Surface Waters ◽  
Arid Zone ◽  
South Australia ◽  
Brushtail Possum ◽  
Protection Measures ◽  
European Settlement ◽  
Introduced Predators ◽  
Average Water ◽  
Cumulative Residual ◽  
Predator Pit

That the brushtail possum was once common and widespread in the arid zone is confirmed by a collation of historical information. Although possums were widespread, detailed records from the Northern Territory and South Australia show that they were most abundant in rocky ranges and outcrops and along watercourses. Possums are now rare in the arid zone. In considering the reasons for the decline of this apparently robust species we have further developed Morton's (1990) model for mammal decline in the arid zone. Our hypothesis is based on the premise that disturbance of refuge habitat patches critical for the survival of the species was occurring at the same time as the country was subjected to a below average water balance. During the period between 1920 and 1970 rainfall was either average or markedly below average with no exceptional rainfalls recorded. Analysis of the rainfall data using a cumulative residual mass curve suggests that sub-surface waters were probably not fully recharged, placing a natural stress on the refuge habitats. At the same time, possum populations were being affected by many disturbing factors introduced by European settlement. Once the populations were reduced, they fell into a 'predator- pit' through depredation by dingoes and introduced predators and were unable to increase in numbers even with the advent of improved conditions. In this paper we identify the need to accurately determine the refuge habitats of a species and then utilise tools such as the cumulative mass residual curve to predict when these habitats will be under most stress. Specific protection measures can then be developed in association with land managers in order to reduce disturbance at the most critical times.

scholarly journals GC/MS Analysis of the Essential Oil from the Oleoresin of Pistacia Atlantica Desf. subsp. Atlantica from Algeria

2008 ◽  
Vol 3 (6) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
Hachemi Benhassaini ◽  
Fatima Z. Bendeddouche ◽  
Zoheir Mehdadi ◽  
Abderrahmane Romane
Keyword(s):  
Peptic Ulcer ◽  
Essential Oil ◽  
Arid Regions ◽  
Chewing Gum ◽  
Minor Constituents ◽  
Pistacia Atlantica ◽  
Naturally Occurring ◽  
Ms Analysis ◽  
Germacrene D ◽  
Semi Arid

The oleoresin of Pistacia atlantica Desf. ssp. atlantica, growing wild in different arid and semi-arid regions of Algeria, is a popular naturally-occurring chewing gum and has been used traditionally in the treatment of peptic ulcer. GC/MS analysis of the essential oil obtained from solvent distillation of the fresh oleoresin has led to the identification of many terpenoids: α-pinene (39.4%), β-pinene (12.9%), carvacrol (11.8%), pinocarvone (5.5%), limonene (5.1%), germacrene-D (2.4%), trans-pinocarveol (2.1%), camphenol (2%), borneol (2%), α-terpene (1.8%), p-cymene (1.7%), terpinolene (1.4%), terpinene-4-ol (1.4%), isopinocarveol (1.1%) and verbenene (1.0%). Other minor constituents were also identified.

scholarly journals Influence of genetic background on albuminuria and kidney injury in Ins2+/C96Y (Akita) mice

2010 ◽  
Vol 298 (3) ◽  
pp. F788-F795 ◽  
Author(s):  
Susan B. Gurley ◽  
Carrie L. Mach ◽  
Johannes Stegbauer ◽  
Jihong Yang ◽  
Kamie P. Snow ◽  
...  
Keyword(s):  
Genetic Background ◽  
Type I Diabetes ◽  
Critical Role ◽  
Kidney Injury ◽  
Strain Differences ◽  
Type I ◽  
Naturally Occurring ◽  
Akita Mice ◽  
Renal Phenotype

Previous studies have shown that Akita mice bearing the Ins2 +/C96Y mutation have significant advantages as a type I diabetes platform for developing models of diabetic nephropathy (DN; Gurley SB, Clare SE, Snow KP, Hu A, Meyer TW, Coffman TM. Am J Physiol Renal Physiol 290: F214–F222, 2006). In view of the critical role for genetic factors in determining susceptibility to DN in humans, we investigated the role of genetic background on kidney injury in Akita mice. To generate a series of inbred Akita mouse lines, we back-crossed the Ins2 C96Y mutation more than six generations onto the 129/SvEv and DBA/2 backgrounds and compared the extent of hyperglycemia and renal disease with the standard C57BL/6- Ins2 +/C96Y line. Male mice from all three Akita strains developed marked and equivalent hyperglycemia. However, there were significant differences in the level of albuminuria among the lines with a hierarchy of DBA/2 > 129/SvEv > C57BL/6. Renal and glomerular hypertrophy was seen in all of the lines, but significant increases in mesangial matrix compared with baseline nondiabetic controls were observed only in the 129 and C57BL/6 backgrounds. In F1(DBA/2 x C57BL/6)- Ins2 +/C96Y mice, the extent of albuminuria was similar to the parental DBA/2- Ins2+/ C96Y line; they also developed marked hyperfiltration. These studies identify strong effects of genetic background to modify the renal phenotype associated with the Ins2 C96Y mutation. Identification of these naturally occurring strain differences should prove useful for nephropathy modeling and may be exploited to allow identification of novel susceptibility alleles for albuminuria in diabetes.

scholarly journals Identification of exosome-like nanoparticle-derived microRNAs from 11 edible fruits and vegetables

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5186 ◽  
Author(s):  
Juan Xiao ◽  
Siyuan Feng ◽  
Xun Wang ◽  
Keren Long ◽  
Yi Luo ◽  
...  
Keyword(s):  
Small Rna ◽  
Fruits And Vegetables ◽  
Critical Role ◽  
Target Prediction ◽  
Edible Plant ◽  
Naturally Occurring ◽  
Mirna Species ◽  
And Function ◽  
Functional Analyses

Edible plant-derived exosome-like nanoparticles (EPDELNs) are novel naturally occurring plant ultrastructures that are structurally similar to exosomes. Many EPDELNs have anti-inflammatory properties. MicroRNAs (miRNAs) play a critical role in mediating physiological and pathological processes in animals and plants. Although miRNAs can be selectively encapsulated in extracellular vesicles, little is known about their expression and function in EPDELNs. In this study, we isolated nanovesicles from 11 edible fruits and vegetables and subjected the corresponding EPDELN small RNA libraries to Illumina sequencing. We identified a total of 418 miRNAs—32 to 127 per species—from the 11 EPDELN samples. Target prediction and functional analyses revealed that highly expressed miRNAs were closely associated with the inflammatory response and cancer-related pathways. The 418 miRNAs could be divided into three classes according to their EPDELN distributions: 26 “frequent” miRNAs (FMs), 39 “moderately present” miRNAs (MPMs), and 353 “rare” miRNAs (RMs). FMs were represented by fewer miRNA species than RMs but had a significantly higher cumulative expression level. Taken together, our in vitro results indicate that miRNAs in EPDELNs have the potential to regulate human mRNA.

scholarly journals In vitro Antioxidant Activities of Natural Polysaccharides: An overview

2019 ◽  
Vol 8 (6) ◽  
pp. 78
Author(s):  
Boris V. Nemzer ◽  
Diganta Kalita ◽  
Alexander Ya Yashin ◽  
Nikolay E. Nifantiev ◽  
Yakov I. Yashin
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activities ◽  
Critical Role ◽  
Free Radical Scavengers ◽  
Therapeutic Effects ◽  
Radical Scavengers ◽  
Glycosidic Bonds ◽  
Naturally Occurring ◽  
Living Organisms

Polysaccharides are naturally occurring biomacromolecules composed of carbohydrate molecules linked by glycosidic bonds. A number of polysaccharides are known to possess beneficial therapeutic effects against inflammation, diabetes, cardiovascular diseases, and cancers. Indeed, polysaccharides are reportedly effective free radical scavengers and antioxidants, thereby playing a critical role in the prevention of damage to living organisms under oxidative stress. In this review we provide an overview of the sources, extraction, and antioxidant activities of some natural polysaccharides.

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