A histoenzymatic study of rat intrafusal muscle fibres.

The histochemical activities of myofibrillar adenosine triphosphatase (ATPase), succinic dehydrogenase (SDH) and alpha glycerophosphate dehydrogenase (alpha-GPD) were studied in intrafusal muscle fibres of rat fast and slow muscles. The ATPase reaction was carried out after the three standard acid preincubations. The cold K2-EDTA preincubated ATPase reaction product was similar to that seen following the regular or alkali-preincubated ATPase reaction, except that the intermediate bag fibres exhibited much higher activity after cold K2-EDTA preincubation. Following either acetic acid solution or cold and room temperature K2-EDTA-preincubation, followed by the ATPase reaction, chain fibres of the fast muscles vastus lateralis and extensor digitorum longus exhibited a very low amount of reaction product as compared with those of the slow soleus. Veronal acetate and K2-EDTA preincubations (and equally preincubation in acetic acid solution) resulted in acid stable ATPase activity along the entire length of the typical bag fibres but only in the polar regions of the intermediate bag fibres. On the basis of differing alpha-GPD reaction, two sub populations of nuclear chain fibres were discovered in one spindle. It is a matter of conjecture, to what extent the histochemical differences of intrafusal fibres from fast and slow muscles reflects functional distinctions in the response to stretch of muscle spindles from fast and slow muscles.     

Distribution of Petroleum and Aromatic Hydrocarbons at a Former Crude Oil and Natural Gas Production Facility

Site characterization and remediation activities were performed at a former crude oil and natural gas production facility prior to redevelopment of the site. Field activities included delineation, excavation and segregation of approximately 1,250,000 m³ of soil impacted by total petroleum hydrocarbons (TPH) and the aromatic volatile organic compounds (VOCs) benzene, toluene, ethylbenzene, and xylenes (hereafter, collectively referred to as BTEX). Petroleum hydrocarbon chain length information was used to determine whether remediation was required in impacted areas, because the site-specific cleanup values for TPH compounds, established by the California State Regional Water Quality Control Board (RWQCB), were based on hydrocarbon chain length. Site-specific cleanup levels were also established by the RWQCB for BTEX. Subsurface investigation activities performed at the site indicated that the mean percentage of condensate and TPH compounds in the gasoline range was significantly greater at depths ranging from 4.6 to 18 m than in shallower samples. There was no significant difference in the mean concentration of BTEX compounds and mean percentage of diesel range and heavier hydrocarbons with depth. The occurrence of BTEX, diesel range, and heavier hydrocarbons at depth may result from preferential pathways for downward migration of contaminants, including blown out wells, abandoned wellbores, and the presence of faults. Vapor phase diffusion may also be a major transport mechanism controlling movement of BTEX compounds beneath the site.     

Development of immunohistochemical characteristics of intrafusal fibres in normal and de-efferented rat muscle spindles

Intrafusal muscle fibres in adult muscle spindles differ in their myosin composition. After selective motor denervation intrafusal muscle fibres develop mature ultrastructural characteristics. In order to evaluate the role of fusimotor innervation on the maturation of the myosin composition of intrafusal muscle fibres we have examined with immunohistochemical techniques i) the postnatal development of muscle spindles in new-born rats and in 7-21 day old rats; ii) muscle spindles in the EDL of 21-day-old rats de-efferented at birth. For the characterization of myosins in intrafusal fibres we used three myosin antisera: antipectoral myosin, antiheart myosin and antiheart myosin adsorbed with muscle powder from the soleus muscle of guinea pig. We show in this study that during development intrafusal fibres change immunoreactivity and that in the absence of motor innervation bag fibres do not fully develop the myosin characteristics of control spindles. We conclude that the maturation of bag1 and bag2 fibres apparently requires next to the inductive influence of sensory axon terminals the presence and activity of fusimotor axons.     

Intrafusal fibre types in rat limb muscle spindles: morphological and histochemical characteristics.

Morphological, histochemical and ultrastructural characteristics of intrafusal fibre types were studied in rat muscle spindles. The existence of three intrafusal fibre types, namely the typical bag, the intermediate bag and the chain fibres was confirmed. Intrafusal fibres differ in diameter, length and number of nuclei in the equatorial zone. Histochemically, typical bag fibres exhibit both alkali- and acid-stable ATPase activity and low SDH activity. Intermediate bag fibres possess low alkali-stable ATPase activity; after acid-preincubation, however, they have low activity only in the juxtaequatorial region, whereas in the polar zones they exhibit high acid-stable ATPase activity. The SDH activity varies from moderate to high. The chain fibres exhibit high alkali-stable and low acid-stable ATPase and high SDH activity in the extensor digitorum longus muscle, whereas in the soleus muscle the acid-stable ATPase activity varies from a low one to a high one, either among individual chain fibres in one spindle, and/or repeatedly along the fibre length. Since there are regional differences in morphological characteristics and in staining properties of intrafusal fibres, a reliable identification of intrafusal fibre types can only be achieved by an analysis of serial sections.     

Changes in ATPase and SDH reactions of the rat extrafusal and intrafusal muscle fibres after preincubations at different pH.

The dependence of adenosine-triphosphatase (ATPase) and succinic dehydrogenase (SDH) histochemical reactions on the pH of the preincubation medium was studied in serial cross sections of 1- to 6-month-old rat extensor digitorum longus (EDL) and soleus (SOL) muscles. The use of a wide spectrum of pH values confirmed the previous results showing that: (1) according to their ATPase and SDH reactions 3 types of extrafusal muscle fibres, i.e., fast-twitch glycolytic (FG), fast-twitch oxidative-glycolytic (FOG) and slow-twitch oxidative (SO) and 3 types of intrafusal muscle fibres, i.e. typical and intermediate nuclear bag fibres and nuclear chain fibres were observed; (2) only acid preincubation (pH 4.35) is necessary to demonstrate the reversal of the ATPase reaction; while (3) alkali preincubation (pH 10.4) does not provide any new important information as compared with ATPase without preincubation. Furthermore, it was shown that: (4) fast-twitch muscle fibres exhibited high ATPase activity on preincubations at pH 4.9 to 10.4, slow-twitch fibres had very high ATPase activity on preincubation at pH 4.3 and 4.5; (5) after preincubation at pH 4.5 two types of FOG fibres were observed, differing in their ATPase activity; (6) in both muscles there were fibres with intermediate ATPase activity both after acid and/or alkali preincubations; (7) the intrafusal muscle fibres exhibited some specific characteristics when compared with extrafusal fibres. In contrast to the ATPase reactions, SDH activity was decreased equally, in both extra- and intrafusal fibres, with increasing acidity and alkality of the preincubation medium.     

Microbiology and geochemistry of great boiling and mud hot springs in the United States Great Basin

A coordinated study of water chemistry, sediment mineralogy, and sediment microbial community was conducted on four >73°C springs in the northwestern Great Basin. Despite generally similar chemistry and mineralogy, springs with short residence time (~5–20 min) were rich in reduced chemistry, whereas springs with long residence time (>1 day) accumulated oxygen and oxidized nitrogen species. The presence of oxygen suggested that aerobic metabolisms prevail in the water and surface sediment. However, Gibbs free energy calculations using empirical chemistry data suggested that several inorganic electron donors were similarly favorable. Analysis of 298 bacterial 16S rDNAs identified 36 species-level phylotypes, 14 of which failed to affiliate with cultivated phyla. Highly represented phylotypes included Thermus, Thermotoga, a member of candidate phylum OP1, and two deeply branching Chloroflexi. The 276 archaeal 16S rDNAs represented 28 phylotypes, most of which were Crenarchaeota unrelated to the Thermoprotei. The most abundant archaeal phylotype was closely related to “Candidatus Nitrosocaldus yellowstonii”, suggesting a role for ammonia oxidation in primary production; however, few other phylotypes could be linked with energy calculations because phylotypes were either related to chemoorganotrophs or were unrelated to known organisms. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.