Bacterial and Fungal Numbers in Ruminal and Cecal Contents of the Blue Duiker (Cephalophus monticola)

[This corrects the article on p. 469 in vol. 57.].     

Rumen Ciliate Protozoa of the Blue Duiker (Cephalophus monticola), with Observations on Morphological Variation Lines Within the Species Entodinium dubardi

ABSTRACT. Protozoal concentrations were determined in rumen and cecal contents of 20 blue duikers ( Cephalophus monticola ). Ten animals of each sex were fed either a high concentrate or high roughage diet. Rumen protozoa were present in 19 of the 20 animals and concentrations ranged from 4.5 to 33.7 × 10⁶ per g of rumen contents. At the higher concentrations, protozoal cells equaled between 30–40% of the total rumen contents volume. No protozoa were found in cecal contents. Weight of rumen contents was higher in females than in males ( P < 0.01), and rumen protozoa concentrations were higher in males ( P < 0.05) and in those animals fed the high concentrate diet ( P < 0.05). All the protozoa were identified as belonging to a single species, Entodinium dubardi . However, an average of about 30% of the E. dubardi cells varied from the typical morphology of this species. These cells appeared to be on variation lines leading toward 7–10 other non-caudate species of Entodinium . The present data were used to evaluate and discuss the concept of variation lines within E. dubardi .     

Effect of Bacterial Contamination on Cecal Size and Cecal Contents of Gnotobiotic Rodents

In the present investigation the effect of various bacterial contaminations of gnotobiotic mice and rats on cecal size is presented. Of the species tested, Bacteroides oralis and Fusobacterium nucleatum did not establish in germ-free mice. Streptococcus mutans, Clostridium difficile, a Neisseria strain and two recent cecal isolates established, but failed to exert an effect upon the cecum of mice. A group K streptococcus and B. fragilis increased the cecal size apparently by increasing the levels of water-soluble protein, peptides, and carbohydrates in the cecal contents. Mixed ileal bacteria decreased the cecal size by preventing accumulation of soluble proteins and carbohydrates in the cecum. A Peptococcus strain caused a reduction by lowering the levels of insoluble material in the cecum. When this strain was combined with two Clostridium isolates and introduced into gnotobiotic rats, 50 to 65% cecal reduction was observed. This polycontamination did not decrease the per cent water of the cecal contents but caused lower levels of both soluble and insoluble material to accumulate in the cecum. No net nitrogen absorption from the distal small intestine occurred in either the germ-free or polycontaminated rats.     

Funktionsanatomische untersuchungen an der kaumuskulatur des blauduckers Cephalophus monticola (Thunberg, 1789) (Mammalia,Bovidae) Investigations on the gross functional anatomy of the muscles of mastication in the blue duiker,Cephalophus monticola (Thunberg, 1789) (Mammalia,Bovidae)

The study of the masticating muscles of ruminants has been rather neglected. Two specimens (skinned head and skull) allowed for the study of the shape of the masticating muscles and their tendinous skeleton. The masseter conformed fairly well to the normal bovid type, the other three muscles very much less so. The outer ear has a special supporting osseous process.     

Temporal and spatial patterns in blue duikers Philatomba monticola and red duikers Cephalophus natalensis

Forest duikers spend a large proportion of the day engaged in sedentary behaviour. Both species were most active shortly after dawn and just before dusk and were relatively more active in habitats of higher quality. Though home-range boundaries were dynamic (changing slightly during the year), core areas were permanent and remained fixed.
Blue duikers showed exclusive family home ranges with no overlap between neighbours, for this species home range and territory are synonymous. Red duiker home-range overlap varied greatly (up to 100% in some cases) indicating the absence of territoriality. Core areas in the home range of both duiker species were usually associated with bedsites. In blue duiker, home ranges and core areas were fixed all year with no overlap between neighbours, while home ranges and core areas of red duikers overlapped extensively. Temporal separation in red duikers is suggested between some individuals and not others.     

Fruit and fibre: the nutritional value of figs for a small tropical ruminant,the blue duiker (Cephalophus monticola)

Tropical forests throughout the world are home to a guild of small ruminants that consume fruit as a substantial portion of their diet. Because the rumen is relatively inefficient at digesting nonstructural carbohydrates and only slowly digests cellulose, the feeding adaptations of frugivorous ruminants are enigmatic. We examined the nutritional value of wild figs to blue duikers, one of the smallest and most frugivorous ruminants, through chemical analyses and a series of digestion trials with six species of wild African figs. These figs were high in fat, protein, cell wall, lignin and Ca : P ratios, low in sugar and starch, and high in unextractable, fibre‐bound tannins when compared with many other fruits. The fibre‐bound tannins and protein caused protein digestibility and nitrogen balance to be consistently low or negative. The high fibre content of the figs allowed duikers to only digest 30–60% of energy contained in the figs. However, duikers were able to consume enough digestible energy to maintain body mass during 4‐day trials. Therefore, a ruminant digestive system is beneficial to mammals eating high fibre, high‐tannin tropical fruit like figs, especially if the mammal is small enough to harvest a sufficient amount to meet its daily energy requirements and has adaptations for reducing the effects of tannins on protein digestibility.     

Intraspecific Variation and Interspecific Differences in the Bacterial and Fungal Assemblages of Blue Tit (Cyanistes caeruleus) and Great Tit (Parus major) Nests

Although interest in the relationship between birds and microorganisms is increasing, few studies have compared nest microbial assemblages in wild passerines to determine variation within and between species. Culturing microorganisms from blue tit (Cyanistes caeruleus) and great tit (Parus major) nests from the same study site demonstrated diverse microbial communities with 32 bacterial and 13 fungal species being isolated. Dominant bacteria were Pseudomonas fluorescens, Pseudomonas putida, and Staphylococcus hyicus. Also common in the nests were the keratinolytic bacteria Pseudomonas stutzeri and Bacillus subtilis. Dominant fungi were Cladosporium herbarum and Epicoccum purpurascens. Aspergillus flavous, Microsporum gallinae, and Candida albicans (causative agents of avian aspergillosis, favus, and candidiasis, respectively) were present in 30%, 25%, and 10% of nests, respectively. Although there were no differences in nest mass or materials, bacterial (but not fungal) loads were significantly higher in blue tit nests. Microbial species also differed interspecifically. As regards potential pathogens, the prevalence of Enterobacter cloacae was higher in blue tit nests, while Pseudomonas aeruginosa—present in 30% of blue tit nests—was absent from great tit nests. The allergenic fungus Cladosporium cladosporioides was both more prevalent and abundant in great tit nests. Using discriminant function analysis (DFA), nests were classified to avian species with 100% accuracy using the complete microbial community. Partial DFA models were created using a reduced number of variables and compared using Akaike’s information criterion on the basis of model fit and parsimony. The best models classified unknown nests with 72.5–95% accuracy using a small subset of microbes (n = 1–8), which always included Pseudomonas agarici. This suggests that despite substantial intraspecific variation in nest microflora, there are significant interspecific differences—both in terms of individual microbes and the overall microbial community—even when host species are closely related, ecologically similar, sympatric, and construct very similar nests.     

Ruminal Bacterial Degradation of Benzo(b)-thien-4-yl Methylcarbamate (Mobam) and Effect of Mobam on Ruminal Bacteria

Mixtures of ruminal bacteria degraded benzo(b)thien-4-yl methylcarbamate (Mobam) to 4-hydroxybenzothiophene, CO(2), and polar product(s). The metabolite, 4-hydroxybenzothiophene, was identified (after acetylation) by comparative infrared and mass spectrometry with an authentic sample. Carbon dioxide and polar product(s) were produced by degradation of the methylcarbamate moiety. Ten previously characterized strains of ruminal bacteria with diverse physiological capabilities did not degrade Mobam. However, three tributyrin-hydrolyzing strains were isolated that did degrade Mobam. Mobam inhibited growth of two of ten strains isolated on Mobam-free glycerol-tributyrin enrichment medium. One of these strains was also sensitive to 2-carbomethoxy-propene-2yl dimethyl phosphate (Phosdrin). Mobam prevented some ruminal bacteria from producing zones of hydrolysis in tributyrin emulsion media and inhibited some ruminal bacteria from degrading 1-naphthyl acetate and fluorescein-3',6'-diacetate.     

Effect of Short-Term Chilling of Rumen Contents on Viable Bacterial Numbers

Anaerobic storage of whole rumen contents at 0°C for 8 and 24 h resulted in viable colony counts which were 113 and 92%, respectively, of the colony count obtained with an unstored sample. No significant differences in the percentages of the total population capable of utilizing glucose, cellobiose, starch, or xylose occurred with storage. Numerous factors were investigated as possible explanations for the increase in bacterial numbers observed after storage for 8 h in ice. Growth and multiplication of bacteria, subsampling of rumen contents, susceptibility to oxygen, lysis of protozoa with the release of viable bacteria, and rumen sampling time did not appear to be involved. Compilation of the data from all 29 of the above experiments gave a mean value for samples stored for 8 h in ice which was 134.8% of the control (P < 0.005). The effect of storage time at 0°C indicated that a significant increase in colony count occurred after 4 h, and, based on these data, 6 h was subsequently used as the standard cold-storage period. Circumstantial evidence supported the hypothesis that storage of rumen contents for 6 h at 0°C appears to alter or to break down the material responsible for cell-to-cell or cell-to-particulate matter attachment. Addition of a surfactant to the anaerobic dilution solution significantly increased total colony count of rumen contents to an extent similar to chilling in ice for 6 h. However, an additive effect was observed when surfactant-containing anaerobic dilution solution was used with samples stored for 6 h at 0°C.     

Bacterial Flora of the Hemolymph of the Blue Crab, Callinectes sapidus: Most Probable Numbers

The hemolymph of 290 freshly collected blue crabs from Chincoteague Bay, Va., was sampled over a 15-month period from August 1968 through November 1969 and most probable numbers of bacteria were determined by tube dilution. The hemolymph of 18% of all crabs sampled was found to be sterile, with 16% sterility in summer and 23% in winter samples. Despite individual variations, male crabs as a group had a higher bacterial hemolymph burden than females, and among both sexes summer counts were higher than winter. The hemolymph of crabs with missing appendages had significantly higher counts than uninjured crabs. The annual mean hemolymph most probable numbers per ml was 2,756 for males, 1,300 for females, and 1,876 for both sexes. The higher bacterial levels found in the hemolymph of male crabs may, in part, be explained by the fact that males, which predominated in the summer samples, had a higher incidence of injury and missing appendages than did females.     

Technique for Estimating Low Numbers of a Bacterial Strain(s) in Soil

A technique is described for obtaining most probable number estimates of the number of cells of a bacterial strain(s) when it is present in low numbers in the soil. The technique is based on the bacteriophage response that is elicited when a known number of bacteriophage for the bacterium of interest is incubated with soil dilutions in a nutrient broth. The technique was evaluated for use with gram-negative bacteria.     

真菌发育过程中的蓝光诱导

本文对多种真菌在发育过程中受蓝光诱导的现象进行了综述。蓝光可以诱导多种真菌的形态发生和发育,包括孢子的产生和菌丝的延伸等。此外,蓝光还可引起真菌的生理和生化改变,如细胞膜对离子的通透性的变化、类胡萝卜素的合成等。真菌也存在一个蓝光信号系统,通过蓝光受体接受蓝光信号,导致了真菌的一系列形态发生和生理生化的变化。     

Temporal Dynamics of Bacterial and Fungal Communities in a Genetically Modified (GM) Rice Ecosystem

We assessed the temporal dynamics of bacterial and fungal communities in a soil ecosystem supporting genetically modified (GM) rice (Oryza sativa L., ABC-TPSP; fusion of trehalose-6-phosphate synthase and phosphatase). Using terminal restriction fragment length polymorphism analysis and real-time quantitative PCR, we compared bacterial and fungal communities in the soils underlying GM rice (ABC-TPSP), and its host cultivar (Nakdong) during growing seasons and non-growing seasons. Overall, the soils supporting GM and non-GM rice did not differ significantly in diversity indices, including ribotype numbers, for either bacteria or fungi. The diversity index (H) in both the bacterial and fungal communities was correlated with water content, dissolved organic carbon (DOC), and ammonium nitrogen, and the correlation was stronger in fungi than in bacteria. Multivariate analysis showed no differences in microbial community structures between the two crop genotypes, but such differences did appear in time, with significant changes observed after harvest. Gene copy number was estimated as 10⁸~10¹¹ and 10⁵~10⁷ per gram of soil for bacteria and fungi, respectively. As observed for community structure, the rice genotypes did not differ significantly in either bacterial- or fungal-specific gene copy numbers, although we observed a seasonal change in number. We summarize the results of this study as follows. (1) GM rice did not influence soil bacterial and fungal community structures as compared to non-GM rice in our system, (2) both bacterial and fungal communities changed with the growth stage of either rice genotype, (3) fungal communities were less variable than bacterial communities, and (4) although several environmental factors, including ammonium nitrogen and DOC correlated with shifts in microbial community structure, no single factor stood out.     

Fungal and Bacterial Activity in Northern Peatlands

Selective inhibition of substrate-induced respiration with antibiotics cycloheximide and streptomycin sulphate provided insight into eukaryotic versus prokaryotic activities in surface peat soil of three Canadian peatlands. Prokaryotic and eukaryotic communities in peatlands are important in the net sequestration of atmospheric carbon dioxide and therefore play a unique role in global carbon cycling. Selective inhibition techniques were generally successful, with a maximum non-target inhibition of only 17%. Assuming that eukaryotic and prokaryotic activities were dominated by fungi and bacteria respectively, across 3 ecologically and hydrologically diverse and spatially dispersed peatlands, we demonstrated bacterial dominance in a bog and a poor fen both with acidic and primarily Sphagnum derived peat soil and in a near pH neutral wetter rich fen with sedge peat (fungal to bacterial activity ratio = 0.31 to 0.68). These results differ in that in other acidic environments, such as conifer forest soils, fungal to bacterial activity ratios are mostly greater than 1 indicative of fungal dominance.     

Comparative Study of Bacterial Groups within the Human Cecal and Fecal Microbiota

The composition of the human cecal microbiota is poorly known because of sampling difficulties. Samples of cecal fluid from eight subjects were collected via an intestinal tube. Feces were also collected. Total anaerobes, facultative anaerobes, bifidobacteria, and Bacteroides were enumerated by culture methods, and the predominant phylogenetic groups were quantified by molecular hybridization using a set of six rRNA-targeted probes. The numbers of strict anaerobes, bifidobacteria, Bacteroides, and members of the Clostridium coccoides group and Clostridium leptum subgroup were lower in the cecum. Facultative anaerobes represented 25% of total bacteria in the cecum versus 1% in the feces.     

Population differentiation in scalation of the Iberian rock lizard (Lacerta monticola)

The rock lizard Lacerta monticola is a climatic relict confined to three mountain ranges and one coastal region of the Iberian peninsula. Scalation was studied in specimens from localities encompassing all major parts of its range. Population differentiation was analysed using analyses of variance, z-transformations of within-locality character-correlations, canonical variate analyses, principal components analysis, and matrix association tests. Substantial differentiation was found between Pyrenees specimens and those from other localities, supporting a recent study which indicated that the Pyrenees populations could represent a different species. Considerable geographic variation is also found among populations from the remaining parts of its range, the pattern of which is not compatible with existing racial categories designated for this species.     

Short-Term Temporal Variability in Airborne Bacterial and Fungal Populations

Airborne microorganisms have been studied for centuries, but the majority of this research has relied on cultivation-dependent surveys that may not capture all of the microbial diversity in the atmosphere. As a result, our understanding of airborne microbial ecology is limited despite the relevance of airborne microbes to human health, various ecosystem functions, and environmental quality. Cultivation-independent surveys of small-subunit rRNA genes were conducted in order to identify the types of airborne bacteria and fungi found at a single site (Boulder, CO) and the temporal variability in the microbial assemblages over an 8-day period. We found that the air samples were dominated by ascomycete fungi of the Hypocreales order and a diverse array of bacteria, including members of the proteobacterial and Cytophaga-Flavobacterium-Bacteroides groups that are commonly found in comparable culture-independent surveys of airborne bacteria. Bacterium/fungus ratios varied by 2 orders of magnitude over the sampling period, and we observed large shifts in the phylogenetic diversity of bacteria present in the air samples collected on different dates, shifts that were not likely to be related to local meteorological conditions. We observed more phylogenetic similarity between bacteria collected from geographically distant sites than between bacteria collected from the same site on different days. These results suggest that outdoor air may harbor similar types of bacteria regardless of location and that the short-term temporal variability in airborne bacterial assemblages can be very large.