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1.
Abstract: Microtubule-associated protein 2 (MAP-2) was studied in the gerbil hippocampus and striatum after transient ischemia. Western immunoblot analysis shows that there is a significant decrease of MAP-2 in the dorsolateral sector of the striatum and a slight decrease of MAP-2 in the CA1 region of the hippocampus 6–12 h after ischemia in the gerbil forebrain. The immunohistochemical staining pattern of MAP-2 in these two regions also shows a loss of immunostaining of MAP-2. In particular, a beaded MAP-2 immunostaining pattern at the apical dendritic region of the CA1 neurons of the hippocampus was found within 12 h after ischemia compared with the smooth dendritic immunostaining of MAP-2 in normal CA1 neurons. In vitro assays of MAP-2 degradation suggest that dendritic loss of immunoreactivity after ischemia seen on western blots may be due to calpain I degradation of MAP-2. Loss of MAP-2 in both the striatum and hippocampus was found to occur earlier than spectrin degradation by western blot analysis. These results suggest that loss of MAP-2 may participate in the initial phase of neuronal dysfunction and that dendritic breakdown may be a first sign of neurodegeneration.  相似文献   

2.
The writer has made an investigation of various samples of basic fuchsin for use in the Endo medium for differentiating the bacteria of the colon-typhoid group. Various different concentrations of the fuchsin samples have been used in making the media. The conclusions are as follows:

American made fuchsins differ markedly in their alcohol solubility properties. They contain materials which are very readily soluble in 95% alcohol, but which are precipitated by sodium sulphite.

This precipitation may be prevented by increasing the dilution of the fuchsin in alcohol.

In order to secure more dependable results in the use of decolorized basic fuchsin as an indicator in Endo Agar, it is advisable to test the fuchsin in different dilutions in alcohol in order to secure a completely decolorized solution. It is also advisable to carefully test those fuchsins which decolorize only in high dilutions with a known organism in Endo agar before relying on it as a satisfactory indicator for the presence of sewage organisms.  相似文献   

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Culturability as an Indicator of Succession in Microbial Communities   总被引:2,自引:0,他引:2  
Successional theory predicts that opportunistic species with high investment of energy in reproduction and wide niche width will be replaced by equilibrium species with relatively higher investment of energy in maintenance and narrower niche width as communities develop. Since the ability to rapidly grow into a detectable colony on nonselective agar medium could be considered as characteristic of opportunistic types of bacteria, the percentage of culturable cells may be an indicator of successional state in microbial communities. The ratios of culturable cells (colony forming units on R2A agar) to total cells (acridine orange direct microscopic counts) and culturable cells to active cells (reduction of 5-cyano-2,3-ditolyl tetrazolium chloride) were measured over time in two types of laboratory microcosms (the rhizosphere of hydroponically grown wheat and aerobic, continuously stirred tank reactors containing plant biomass) to determine the effectiveness of culturabilty as an index of successional state. The culturable cell:total cell ratio in the rhizosphere decreased from approximately 0.25 to less than 0.05 during the first 30-50 days of plant growth, and from 0.65 to 0.14 during the first 7 days of operation of the bioreactor. The culturable cell:active cell ratio followed similar trends, but the values were consistently greater than the culturable cell:total cell ratio, and even exceeded I in early samples. Follow-up studies used a cultivation-independent method, terminal restriction fragment length polymorphisms (TRFLP) from whole community DNA, to assess community structure. The number of TRFLP peaks increased with time, while the number of culturable types did not, indicating that the general decrease in culturability is associated with a shift in community structure. The ratio of respired to assimilated C-14-labeled amino acids increased with the age of rhizosphere communities, supporting the hypothesis that a shift in resource allocation from growth to maintenance occurs with time. Results from this work indicate that the percentage of culturable cells may be a useful method for assessing the successional state of microbial communities.  相似文献   

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Flooding p-aminodimethylaniline monohydrochloride on fat emulsion agar inoculated with certain types of microorganisms frequently results in marked color changes in the fat globules. It is shown in this paper that the colors result from the increased solubility in fat and fatty acids of this dye as it becomes oxidized. Some of the acids oxidize the dye on contact and therefore color very quickly; fats become colored only when some other agent oxidizes the dye. The characteristic color reactions with certain fats and fatty acids are described for various degrees of oxidation of the dye; this suggests the explanation for the colors observed in the inoculated globules flooded with this dye. A table is included showing the colors in globules of oil that were inoculated with 39 pure cultures of bacteria.  相似文献   

9.
Krut’ko  V. N.  Dontsov  V. I. 《Biophysics》2020,65(1):165-171
Biophysics - Abstract—Using data gathered from 40 countries throughout a historical period covering two and a half centuries, we studied the peculiarities of age-related changes in the aging...  相似文献   

10.
Accurate indicators of fecal pollution are needed in order to minimize public health risks associated with wastewater contamination in recreational waters. However, the bacterial indicators currently used for monitoring water quality do not correlate with the presence of pathogens. Here we demonstrate that the plant pathogen Pepper mild mottle virus (PMMoV) is widespread and abundant in wastewater from the United States, suggesting the utility of this virus as an indicator of human fecal pollution. Quantitative PCR was used to determine the abundance of PMMoV in raw sewage, treated wastewater, seawater exposed to wastewater, and fecal samples and/or intestinal homogenates from a wide variety of animals. PMMoV was present in all wastewater samples at concentrations greater than 1 million copies per milliliter of raw sewage. Despite the ubiquity of PMMoV in human feces, this virus was not detected in the majority of animal fecal samples tested, with the exception of chicken and seagull samples. PMMoV was detected in four out of six seawater samples collected near point sources of secondary treated wastewater off southeastern Florida, where it co-occurred with several other pathogens and indicators of fecal pollution. Since PMMoV was not found in nonpolluted seawater samples and could be detected in surface seawater for approximately 1 week after its initial introduction, the presence of PMMoV in the marine environment reflects a recent contamination event. Together, these data demonstrate that PMMoV is a promising new indicator of fecal pollution in coastal environments.Existing wastewater treatment practices are not always effective at removing the large number of pathogens (bacteria, protists, and viruses) present in human feces (17, 42, 47-49, 51). Therefore, wastewater discharges into the environment can have a negative impact on human health. Recreational waters throughout the United States are monitored for the presence of fecal pollution as a means of limiting public exposure to pathogens in areas impacted by wastewater discharges (44). The presence of pathogenic viruses in aquatic environments is an important parameter to consider in the evaluation of water quality. However, the bacterial indicators currently used to detect fecal contamination, such as fecal coliforms and enterococci, often do not correlate with the presence of feces-associated viruses and other pathogens (5, 10, 26, 33, 37, 51). In response, several researchers have proposed the use of viral indicators as a more effective method for monitoring wastewater contamination and the associated risks to public health (11, 14, 31).To date, the majority of the proposed viral indicators of fecal pollution are enteric viruses transmitted via the fecal-oral route (4). Enteric viruses present in raw sewage (including members of the families Adenoviridae, Caliciviridae, Picornaviridae, and Reoviridae and of the genus Anellovirus) have been used in several previous studies to identify fecal pollution in the environment (7, 8, 11, 12, 13, 18, 19, 27, 28, 32-36, 38, 50, 51). Of the enteric viruses that have been used as indicators, only the adenoviruses were ubiquitously found in raw sewage samples collected throughout the United States (41). Picobirnaviruses and Torque teno virus are abundant in raw sewage from some regions and thus have also been proposed as indicator viruses (15, 41). However, one potential problem with the use of human viruses as indicators is that their abundance in wastewater depends on the degree of infection and shedding in the human population at any given time.In addition to viruses infecting humans, other viruses shed in feces may be useful for indicating wastewater pollution. The plant pathogen Pepper mild mottle virus (PMMoV) was the most abundant virus found in a metagenomic survey of RNA viruses from human feces (52). PMMoV is a positive-sense, single-stranded RNA virus that belongs to the Tobamovirus genus and infects hot, bell, and ornamental peppers (Capsicum spp.) (9). The nonenveloped, rod-shaped PMMoV virions are extremely stable (9) and have been demonstrated to retain their infectivity for plants after passage through the human gut (52). PMMoV originates from processed pepper products (e.g., hot sauce and curry) and is excreted in human feces at concentrations of 1 million to 1 billion viruses per g (dry weight) (52). Since the presence of PMMoV in human feces is dietary in origin, this plant pathogen may be more abundant in the healthy human population than viruses that cause human disease.This study analyzed the presence of PMMoV in raw sewage and treated wastewater samples collected from wastewater treatment facilities throughout the coastal United States. To determine if PMMoV is a human-specific indicator useful for tracking the source of fecal pollution, fecal samples from numerous animals were tested for this virus. Finally, the presence of PMMoV in marine environments exposed to wastewater was determined and compared to that of other microbial indicators. The results of this work demonstrate that PMMoV is a promising indicator of fecal pollution.  相似文献   

11.
Representatives of 15 nematode genera were viewed with 450-490-nm epi-illumination and found to autofluoresce. The autofluorescence was limited to 1-5-μm-d globules in the intestinal cells of live nematodes. When adult Pratylenchus penetrans or Caenorhabditis elegans were killed with formaldehyde, freezing, or heat, autofluorescence dispersed throughout the body. Mixed stages of P. penetrans were killed by freezing at several different temperatures. Estimates of survival based on autofluorescence dispersal matched estimates based on mobility more closely than did estimates based on the vital stain, eosin-y.  相似文献   

12.
This study aims to investigate the relationship between serum macro- and trace element contents and the degree of disk degeneration in patients with intervertebral disk herniation (IDH). This study was carried out on 69 subjects (30 women and 39 men) diagnosed with IDH. Blood samples of the subjects were collected, and serum concentrations of the elements that include macroelements, such as calcium, phosphorus, potassium, sodium, and magnesium, and trace elements, such as zinc, iron, copper, and selenium, were determined using inductively coupled plasma–atomic emission spectrometry. Magnetic resonance imaging (MRI) examination of the entire lumbar region of the vertebral column was conducted using a 1.5-T MRI scanner. The degree of disk degeneration was classified into three categories. Correlation analysis between the degree of disk degeneration and the serum element was performed using SPSS 16.0. In the correlation analysis between the degree of disk degeneration and the element contents, only calcium was found to be negatively correlated with the degree of disk degeneration (r?=??0.332, P?<?0.01). Comparison results between male and female groups showed no significant difference in the element content and in the degree of disk degeneration (P?>?0.05). Moreover, the serum calcium content showed a significant correlation with the degree of disk degeneration, suggesting that the serum calcium concentration can be used as an indicator of intervertebral disk degeneration prognosis.  相似文献   

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Experiments are described in which we used a mass spectrometer to monitor O2 uptake of enclosed soil samples as a function of temperature. We found that an Arrhenius plot of the rate of O2 uptake showed pronounced local maxima attributable to biological activity, whereas similar plots of rates obtained with abiotic soils yielded straight lines. This procedure thus provides a basis for distinguishing biological from chemical activity for reactions, such as O2 uptake, that can occur via either biological or chemical pathways.  相似文献   

15.
A new method for determining a small amount of polyethyleneglycol (mol. wt. about 4,000) in feces or ingesta was described. The rates of flow and excretion along the swine digestive tract were compared between polyethyleneglycol and chromic oxide used as an indicator for digestion studies.

The former was removed from stomach more rapidly than the latter, and would be delayed in its passage along large intestine owing to absorption of water therein. There was a general agreement between the excretion variations of both indicators. Recoveries during feces collection periods were lower for polyethyleneglycol than for chromic oxide. However, there was no essential difference between both indicators in retention time in the digestive tract, calculated following the idea of Castle.  相似文献   

16.

Purpose

To investigate the relationship between distal symmetric peripheral neuropathy and early stages of autonomic bladder dysfunction in type 2 diabetic women.

Materials and Methods

A total of 137 diabetic women with minimal coexisting confounders of voiding dysfunction followed at a diabetes clinic were subject to the following evaluations: current perception threshold (CPT) tests on myelinated and unmyelinated nerves at the big toe for peroneal nerve and middle finger for median nerve, uroflowmetry, post-void residual urine volume, and overactive bladder (OAB) symptom score questionnaire. Patients presenting with voiding difficulty also underwent urodynamic studies and intravesical CPT tests.

Results

Based on the OAB symptom score and urodynamic studies, 19% of diabetic women had the OAB syndrome while 24.8% had unrecognized urodynamic bladder dysfunction (UBD). The OAB group had a significantly greater mean 5 Hz CPT test value at the big toe by comparison to those without OAB. When compared to diabetic women without UBD, those with UBD showed greater mean 5 Hz CPT test values at the middle finger and big toe. The diabetic women categorized as C-fiber hyposensitivity at the middle finger or big toe by using CPT test also had higher odds ratios of UBD. Among diabetic women with UBD, the 5 Hz CPT test values at the big toe and middle finger were significantly associated with intravesical 5 Hz CPT test values.

Conclusions

Using electrophysiological evidence, our study revealed that hyposensitivity of unmyelinated C fiber afferents at the distal extremities is an indicator of early stages diabetic bladder dysfunction in type 2 diabetic women. The C fiber dysfunction at the distal extremities seems concurrent with vesical C-fiber neuropathy and may be a sentinel for developing early diabetic bladder dysfunction among female patients.  相似文献   

17.
Hydrophobic polymer amide (HPA) could have been one of the first normal density materials to accrete in space. We present ab initio calculations of the energetics of amino acid polymerization via gas phase collisions. The initial hydrogen-bonded di-peptide is sufficiently stable to proceed in many cases via a transition state into a di-peptide with an associated bound water molecule of condensation. The energetics of polymerization are only favorable when the water remains bound. Further polymerization leads to a hydrophobic surface that is phase-separated from, but hydrogen bonded to, a small bulk water complex. The kinetics of the collision and subsequent polymerization are discussed for the low-density conditions of a molecular cloud. This polymer in the gas phase has the properties to make a topology, viz. hydrophobicity allowing phase separation from bulk water, capability to withstand large temperature ranges, versatility of form and charge separation. Its flexible tetrahedral carbon atoms that alternate with more rigid amide groups allow it to deform and reform in hazardous conditions and its density of hydrogen bonds provides adhesion that would support accretion to it of silicon and metal elements to form a stellar dust material.  相似文献   

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The swelling capacity of cell walls isolated from different parts of lupine root was investigated. The water content in fragments of intact roots (Q) and swelling coefficient of standardized samples of cell walls (Kcw) were determined, and the dependences of Q and Kcw on the distance from the root tip (L) were plotted. It was shown that the change in Q value along the stretch of the lupine root reaches its maximum at distances of 1.5-6 cm or 7-12 cm from the root tip in 7-day-old and 14-day-old seedlings, respectively, whereas the Kcw value distribution over the root length is virtually invariable. In the radial direction, both the Q and Kcw values in cortex tissues are about twice higher than in the central cylinder. In our opinion, the changes of both Q and Kcw in the radial direction are associated with different degrees of cross-linking between polymer chains in cell wall structures of root cortex and central cylinder. The results of measurement of the Kcw value are consistent with the widely accepted mechanisms of water transport in roots in the radial direction. These data show that water transport through apoplast to the border between the cortex and central cylinder is accompanied by an increase in the resistance to water flow. Among other factors, this increase is due to a greater degree of cross-linking between cell wall polymers in the central cylinder. The results of measurement of the swelling coefficient of standardized cell wall samples in water and in 10 mM KCl at different pH values show that the swelling capacity of root cell walls varies according to the physicochemical properties of synthetic ion exchangers. Cell walls shrink (cell wall volume decreases) as ion concentration in solution increases and pH decreases. This causes an increase in the hydraulic resistance (or a decrease in the hydraulic conductivity) of apoplast. It was concluded that swelling is determined by the physicochemical properties of the cell wall, whereas the change in the swelling capacity induced by variation of external or internal conditions is an element of the mechanism of regulation of volume water flow in roots.  相似文献   

20.
《Anthrozo?s》2013,26(4):427-440
ABSTRACT

Associations between mammalian coat color and behavior have been investigated in a number of species, most notably the study of silver foxes by the Institute of Cytology and Genetics at the Russian Academy of Sciences. However, the few studies conducted regarding a potential relation between coat color and domestic cat personality have shown mixed results, even though many people believe that differently colored cats have distinct personalities. Understanding how humans might perceive personality in relation to coat color may have important ramifications regarding whether cats are relinquished to shelters or adopted from them. In order to assess human perceptions of differently colored cats, we conducted an anonymous, online survey, using a 7-point Likert scale and 10 terms describing personality traits that were chosen based on previous studies of animal personality. This survey examined how people assigned these given terms (active, aloof, bold, calm, friendly, intolerant, shy, stubborn, tolerant, and trainable) to five different colors of cats (orange, tricolored, white, black, and bi-colored). There were significant differences in how participants in this study chose to assign personality terms to differently colored cats. For example, participants (n = 189) were more likely to attribute the trait “friendliness” to orange cats, “intolerance” to tri-colored cats, and “aloofness” to white and tri-colored cats. No significant differences were found for “stubbornness” in any colors of cats. White cats were seen as less bold and active and more shy and calm than other colors of cats. While survey respondents stated that they placed more importance on personality than color when selecting a companion cat, there is some evidence that they believe the two qualities are linked. We anticipate our findings will be relevant to further study in domestic cat personality and to those who work in animal rescue, particularly in how shelters promote differently colored cats and educate potential adopters.  相似文献   

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