The adaptive significance of male polymorphism in the acarid mite Caloglyphus berlesei

Summary Two forms of males occur in the acarid mite, Caloglyphus berlesei. One of them uses its thickened third pair of legs to kill other males; the other, without modified legs, does not attack other males. Previous studies have shown that the form of the male is environmentally determined: fighter males develop only at low population densities and their development can be suppressed by substances emanating from dense colonies. In this study, the duration of development, longevity and virility of the two male morphs were measured. The only significant difference was that fighters had a shorter development time between the two last moults. In another experiment, two groups of colonies were maintained under the same conditions but had different numbers of individuals: small colonies contained 2 fighters and 2 non-fighters, whereas large colonies contained 30 males of each type. The relative reproductive success of both morphs was estimated from numbers of matings. In small colonies, the estimated reproductive success (ERS) was significantly higher for fighters than for non-fighters, mainly because in over 50% of these colonies a single fighter male managed to kill all the rival males and monopolize the females. The opposite was true in large colonies, in which non-fighters achieved significantly higher ERS, mainly because the fighters were killed in fights more often than the non-fighters. This implies that the ratio of costs to benefits obtained by adopting the fighter-male strategy increases with the number of rival males, which may explain conditional male development in C. berlesei.     

The potential of epiphytic hydrocarbon-utilizing bacteria on legume leaves for attenuation of atmospheric hydrocarbon pollutants

The leaves of two legumes, peas and beans, harbored on their surfaces up to 9×10? cells g?1 of oil-utilizing bacteria. Less numbers, up to 5×10? cells g?1 inhabited leaves of two nonlegume crops, namely tomato and sunflower. Older leaves accommodated more of such bacteria than younger ones. Plants raised in oily environments were colonized by much more oil-utilizing bacteria than those raised in pristine (oil-free) environments. Similar numbers were counted on the same media in which nitrogen salt was deleted, indicating that most phyllospheric bacteria were probably diazotrophic. Most dominant were Microbacterium spp. followed by Rhodococcus spp., Citrobacter freundii, in addition to several other minor species. The pure bacterial isolates could utilize leaf tissue hydrocarbons, and consume considerable proportions of crude oil, phenanthrene (an aromatic hydrocarbon) and n-octadecane (an alkane) in batch cultures. Bacterial consortia on fresh (but not on previously autoclaved) leaves of peas and beans could also consume substantial proportions of the surrounding volatile oil hydrocarbons in closed microcosms. It was concluded that phytoremediation through phyllosphere technology could be useful in remediating atmospheric hydrocarbon pollutants.     

Biochemical studies on the terrestrial snail,Eubania vermiculata (müller)treated with some pesticides

Abstract

The in vivo effects of methomyl, thiodicarb and metaldehyde on total soluble proteins, total lipids and glycogen content, in addition, the activity of glutamic oxaloacetic transaminase, (GOT), (GPT) glutamic pyruvic transaminase and catalase (CAT) enzymes of terrestrial E. vermiculata snails was studied. The experimental snails were treated with low concentration of 0.2% bran bait w/w of the pesticides for a period of 1,3,5,7 and 10 days. The results showed that methomyl and thiodicarb lead to significant reduction in total soluble proteins, lipids, and glycogen content, while significant increases in the activity of all enzymes tested were noted. Metaldehyde treatment showed no significant effect on total soluble proteins, lipids and GOT level, whereas a significant increase in GPT and CAT enzymes was observed. Also, metaldehyde resulted a significant reduction in glycogen content of snails.     

Colony size,but not density,affects survival and mating success of alternative male reproductive tactics in a polyphenic mite,Rhizoglyphus echinopus

Among acarid mites, a number of species are characterised by the presence of discontinuous morphologies (armed heteromorphs vs. unarmed homeomorphs) associated with alternative mating tactics (fighting vs. scramble competition). In Rhizoglyphus echinopus, expression of the fighter morph is suppressed, via pheromones, in large, dense colonies. If this mechanism is adaptive, fighters should have relatively lower fitness in large and/or dense colonies, due to costs incurred from fighting, which is often fatal. In order to test these predictions, we quantified the survival and mating success of fighters and scramblers in colonies of equal sex and morph ratios; these colonies either differed in size (4, 8, or 32 individuals) but not density or differed in density but not size (all consisted of 8 individuals). We found that the relative survival and mating success of fighters was inversely related to colony size, but we did not find a significant effect of colony density. The higher mating success of fighters in small colonies was due to the fact that, after killing rival males, these fighters were able to monopolise females. This situation was not found in larger colonies, in which there was a larger number of competitors and fighters suffered relatively higher mortality. These results indicate that morph determination, guided by social cues, allows for the adaptive adjustment of mating tactics to existing demographic conditions.     

Biochemical studies on the terrestrial snail, Eubania vermiculata (Müller) treated with some pesticides.

The in vivo effects of methomyl, thiodicarb and metaldehyde on total soluble proteins, total lipids and glycogen content, in addition, the activity of glutamic oxaloacetic transaminase, (GOT), (GPT) glutamic pyruvic transaminase and catalase (CAT) enzymes of terrestrial E. vermiculata snails was studied. The experimental snails were treated with low concentration of 0.2% brain bait w/w of the pesticides for a period of 1,3,5,7 and 10 days. The results showed that methomyl and thiodicarb lead to significant reduction in total soluble proteins, lipids, and glycogen content, while significant increases in the activity of all enzymes tested were noted. Metaldehyde treatment showed no significant effect on total soluble proteins, lipids and GOT level, whereas a significant increase in GPT and CAT enzymes was observed. Also, metaldehyde resulted a significant reduction in glycogen content of snails.     

Used lubricating oil recycling using hydrocarbon solvents

A solvent extraction process using new hydrocarbon solvents was employed to treat used lubricant oil. The solvents used were liquefied petroleum gas (LPG) condensate and stabilized condensate. A demulsifier was used to enhance the treatment process. The extraction process using stabilized condensate demonstrated characteristics that make it competitive with existing used oil treatment technologies. The process is able to reduce the asphaltene content of the treated lubricating oil to 0.106% (w/w), the ash content to 0.108%, and the carbon residue to 0.315% with very low levels of contaminant metals. The overall yield of oil is 79%. The treated used oil can be recycled as base lubricating oil. The major disadvantage of this work is the high temperature of solvent recovery. Experimental work and results are presented in detail.     

Lipids,and their constituent fatty acids,ofPhaeocystis sp. from the Arabian Gulf

This paper reports on the firstPhaeocystis sp. (hereafterPhaeocystis) bloom in the Arabian Gulf. Total lipids from threePhaeocystis colonies sampled in November 1987 and in March and May 1988, comprised ca 11.0% of the dry biomass. Triacylglycerols (TG) and/or free fatty acids (FA) predominated in the lipids of all three samples. Polar lipids consisted of mixtures of phospholipids and glycolipids. Diacylglycerotrimethylhomoserines (DGTH) were present in all extracts, whilst conventional phospholipids only occurred in low concentrations. The predominant glycolipids were monogalactosyldiacylglycerols (MGDG) digalactosyldiacylglycerols (DGDG), sulfoquinovosyldiacylglycerols (SQDG) and steryl glycosides (SG). The predominant fatty acids in the total lipids of all three samples were palmitic (16:0) and oleic (18:1) acids. Total lipids of the November sample contained the smallest proportion of palmitic and the largest of polyunsaturated fatty acids (PUFA) — especially C₁₆. The proportion of PUFA was considerable in individual polar lipids. C₁₆ PUFA were more common in individual polar lipid classes of the November and March samples than that of May. The concentration of constituent C₁₈ PUFA was relatively low. PUFA with chains longer than 18 C atoms only occurred in very low concentrations, and were confined to certain polar and nonpolar lipid classes of the November sample only.     

The ameliorative effect of kaempferol against CdCl2- mediated renal damage entails activation of Nrf2 and inhibition of NF-kB

Environmental Science and Pollution Research - This study evaluated the nephroprotective effect of kaempferol against cadmium chloride (CdCl2) -induced nephropathy in rats. It also investigated if...     

Crude oil and hydrocarbon-degrading strains of Rhodococcus rhodochrous isolated from soil and marine environments in Kuwait

Soil and marine samples collected from different localities in Kuwait were screened for microorganisms capable of oil degradation. Both fungi and bacteria were isolated. The fungal flora consisted of Aspergillus terreus, A. sulphureus, Mucor globosus, Fusarium sp. and Penicillum citrinum. Mucor globosus was the most active oil degrading fungus isolated. Bacterial isolates included Bacillus spp. Enterobacteriaceae, Pseudomonas spp., Nocardia spp., Streptomyces spp.,and Rhodococcus spp. Among these Rhodococcus strains were the most efficient in oil degradation and, relatively speaking, the most abundant. Bacterial and fungal isolates differed in their ability to degrade crude oil, with Rhodococcus isolates being more active that fungin in n-alkane biodegradation, particularly in the case of R. rhodochrous. In addition to medium chain n-alkanes, fungi utilized one or more of the aromatic hydrocarbons studied, while bacteria failed to do so. R. rhodochorous KUCC 8801 was shown by GLC and post-growth studies to be more efficient in oil degradation than isolates known to be active oil degraders.