Immersion In Lactic Acid Research Articles

Assessment of in-plant decontamination of broiler carcasses by immersion in hot water and lactic acid in Norway

This study investigated the effect of hot-water immersion, at different water temperatures and exposure times, on the microbiological loads on broiler carcasses. The combinations tested were 70 °C for 3 s, 80 °C for 3 s and 6 s, and 90 °C for 3 s. The separate effects of immersion in 5% lactic acid at 15 °C for 3 s and the on-line cold-water spray carousel on microbiological loads were also investigated. The study was conducted at a commercial broiler abattoir in Norway, where 110 carcasses were collected directly from the slaughter line after evisceration but before the cold-water carousel and brought to a separate room for immersion testing and microbiological sampling. Each carcass was assessed for skin injuries and discoloration post treatment, and sampling was by whole carcass rinse. Skin damage following hot-water treatment was not observed. A white coating developed on the skins of carcasses treated with 5% lactic acid after drying. For untreated carcasses, total plate count (TPC) mean was 4.9 log cfu/ml and E. coli mean was 4.0 log cfu/ml. Mean TPC were significantly lower (by 1.0–1.1 log cfu/ml) for carcasses immersed in hot water at 80 °C (3 and 6 s) and 90 °C. Only immersion in 80 °C for 6 s significantly reduced the E. coli mean (by 1.1 log cfu/ml). Immersion in 5% lactic acid reduced TPC by 4.0 log cfu/ml and E. coli by 3.9 log cfu/ml, with 9 of 10 samples below the detection level for E. coli. The cold-water carousel resulted in an insignificant reduction in TPC and E. coli levels. In conclusion, immersion for 6 s in 80 °C was the most effective hot-water treatment. Although lactic acid immersion is more effective, it is currently not permitted to use on broiler carcasses in Europe.

A comparative evaluation of fracture toughness, flexural strength, and acid buffer capability of a bulk-fill alkasite with high-strength glass-ionomer cement: An in vitro study

Although glass-ionomer cement (GIC) has many unique properties and advantages, it still lacks favorable mechanical properties. Cention N is a recent alkasite material with excellent mechanical properties. The purpose of this study was to compare the mechanical properties (fracture toughness [FT] and flexural strength [FS]) and acid buffer capability of an alkasite material to GIC. In this in vitro study, a total of 60 samples were prepared using Cention N or GIC. Twenty specimens (n = 10) were prepared using beam-shaped Teflon molds for FS, and twenty specimens (n = 10) were prepared with a similar mold with a notch for FT. These were evaluated on a universal testing machine using a three-point bend test. Twenty (n = 10) disk-shaped specimens were prepared for acid buffer capability. The samples were stored in distilled water for a week. This was followed by immersion in lactic acid with a pH of 4 for calculation of the materials acid buffering capacity at 30 and 60 min from exposure using a pH meter. The data obtained were tabulated and subjected to Kolmogorov-Smirnov test and Shapiro-Wilk test to assess the normal distribution and further analyzed using the Student's t-test to assess the level of significance, P < 0.05 was considered statistically significant. The mean FT, FS, and acid buffer capability of Cention N were significantly higher than GIC at P < 0.05. The present study surmised that Cention N exhibited higher FT, FS, and acid buffer capability than GIC.

In-Plant Intervention Validation of a Novel Ozone Generation Technology (Bio-Safe) Compared to Lactic Acid in Variety Meats.

The objective of this experiment was to compare the antimicrobial efficacy of an aqueous ozone intervention and a lactic acid solution on natural microbiota of variety meats in a commercial beef processing plant. EZ-Reach™ swabs were used to collect 100 cm2 area samples before and after ozone and lactic acid intervention application for three different offals (head, heart, and liver). Each repetition included 54 samples per variety meat and antimicrobial for a total of 162 samples per repetition. Enumeration of total aerobic bacteria (APC) and Escherichia coli (EC) was performed on each sample. Microbial counts for both microorganisms evaluated were significantly reduced (p < 0.001) after lactic acid immersion (2–5%) and ozone intervention for all variety meats, with the exception of ozone intervention in EC counts of the heart samples. APC after lactic acid intervention was reduced on average by 1.73, 1.66, and 1.50 Log CFU/sample in the head, heart, and liver, respectively, while after ozone intervention, counts were reduced on average by 1.66, 0.52, and 1.20 Log CFU/sample. EC counts after lactic acid intervention were reduced on average by 0.96, 0.79, and 1.00 Log CFU/sample in the head, heart, and liver, respectively, while after ozone intervention, counts were reduced on average by 0.75, 0.62, and 1.25 Log CFU/sample. The aqueous ozone antimicrobial scheme proved to be a promising intervention for the in-plant reduction of indicator levels in variety meats, specifically heads, hearts, and livers.

Corrosion of titanium implants and connected prosthetic alloys using lactic acid immersion test

Background/purpose: Combination of dental titanium implants with other prosthetic metallic components may lead to metal ion release that increases the risk of adverse reactions in patients. The present study therefore aimed to determine in vitro metal ion dissolution from different alloy combinations. Materials and methods: Dental alloys were subjected to a lactic acid immersion test together with titanium implants and matched with controls. Between day 1 and 38, open direct current potentials (DCP) between the samples and the electrolyte were recorded and metal dissociation inside the electrolyte was assessed using ICP-MS. Results: Absolute DCPs of the different alloys increased significantly (p&lt;0.001) from 100-150mV to 490-580 mV within the first two weeks of immersion, dropping to about 450mV later on largely independent of the material. Titanium showed highest dissociation rates (2.00-12.06µg/cm2 per day; p=0.0002); all other components demonstrated poor corrosive dissolution (&lt;0.6µg/cm2 per day). After immersion of 38 days, titanium still yielded high dissociation (0.64-1.38µg/cm2 per day) for all test groups. Presence of fine gold inside the electrolyte significantly increased dissociation of titanium (p=0.027). Dissociation of iron indicated contamination from tool components used for implant production. Optical examination of non-precious metal surfaces showed no corrosive discoloration after 5 or 26 weeks of lactic acid immersion. Conclusion: Within the limitations of this study, there is no objection against the use of non-precious alloys for the fabrication of components and prostheses supported on titanium implants if gold is not present inside the same electrolyte.

The Efficacy of Lactic Acid Immersion as an Antimicrobial Intervention in Beef Sub-Primal Fabrication

ObjectivesTo perform an in-plant validation of a lactic acid immersion (2–5%) intervention in 6 different subprimals on the fabrication floor.Materials and MethodsSwab samples (n = 324) were taken before and after intervention application from six different processing lines. Each subprimal had a 500 cm2 area swabbed using sterile materials. Each repetition included 18 samples per line, 9 before and 9 after intervention, for a total of 108 samples per repetition. Swab samples were immediately chilled and shipped overnight to the TTU Food Microbiology laboratory for microbial analysis. Samples were stomached at 230 rpm for 30 s and for each subprimal, 3 individual samples were composited into one. Serial dilutions were performed and 1ml of each composite was plated onto Enterobacteriaceae, aerobic plate count, Escherichia coli and coliform Petrifilms in duplicate. Counts were transformed into LogCFU/cm2 and statistical analysis was performed to determine differences between before and after treatment samples with a 0.05 probability threshold.ResultsMicrobial counts of all four microorganisms evaluated were significantly reduced (P &lt; 0.05) after the lactic acid immersion (2–5%) intervention application in subprimals. Total coliform counts before and after treatment were 0.31 and 0.06 LogCFU/cm2, respectively. Enterobacteriaceae counts in the subprimals were in average 0.40 LogCFU/cm2 before interventions and 0.06 LogCFU/cm2 after intervention application. Overall aerobic plate counts were 1.77 LogCFU/cm2 before intervention and 1.14 LogCFU/cm2 after intervention. Generic E. coli counts after intervention were lower than the detection limit (&lt; 1 CFU/20 cm2).ConclusionBased on data collected, it is reasonable to conclude that the lactic acid immersion intervention is effective in reducing common microbial indicators on subprimals inside the fabrication floor, improving the safety of the product.

PENGARUH KONSENTRASI DAN LAMA PERENDAMAN BAHAN DENGAN ASAM LAKTAT SEBELUM PENGERINGAN TERHADAP KARAKTERISTIK BUBUK BUNGA KENIKIR (Tagetes erecta L.)

Marigold flowers (Tagetes erecta L.) have the potential as natural dyes that contain color pigments from carotenoid compounds. The purpose of this study was to determine the effect of lactic acid concentration and soaking time before drying on the characteristics of kenikir flower powder and determine the concentration of lactic acid and the duration of lactic acid immersion before the best combustion to produce kenikir flower powder. This study used a randomized block design using factorial patterns with 2 factors. The first factor is the concentration of lactic acid consisting of 3 levels: 0,5, 1,0, and 1,5%. The second factor is the immersion time consisting of 3 levels: 60, 90, and 120 minutes. The results showed that the treatment of lactic acid concentration affected the total carotenoid level, brightness (L *), redness level (a *) yellowish level (b *) but did not significantly affect the water content. The treatment of immersion time did not affect the total carotenoid level, brightness level (L*), yellowish level (a*), redness level (b*) and water content. Immersion treatment with a concentration of 1,5% and 90 minutes soaking time is the best treatment for producing kenikir flower powder with characteristics namely water content 16,71%, total carotenoid content 18,77%, brightness level (L*) 38,23, redness level (a*) 29,02, yellowish level (b*) 51,93.&#x0D; Keywords : Tagetes erecta L., lactic acid, karotenoid, color

Combination effect of saturated or superheated steam and lactic acid on the inactivation of Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes on cantaloupe surfaces

The purpose of this study was to evaluate the effectiveness of the combination treatment of lactic acid immersion and saturated or superheated steam (SHS) on inactivation of foodborne pathogens on cantaloupes. Saturated steam (SS) treatments were performed at 100 °C, while SHS treatments were delivered at either 150 or 200 °C. Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes-inoculated cantaloupes were exposed to 2% lactic acid or sterile distilled water for 1 min followed by a maximum of 20 s of SS or SHS. Populations of each of the three pathogens on cantaloupes were reduced to under the detection limit (1.0 log CFU/cm2) after the combination treatment of 2% lactic acid and 200 °C steam for 20 s. To compare the effect of the lactic acid treatment method, we conducted spray application with 2% lactic acid combined with SS or SHS treatment; however, no significant log reduction differences were found between immersion and spraying techniques. After combination treatment of cantaloupes for 20 s, color and maximum load values (a characteristic of texture) were not significantly different from those of untreated controls. The results of this study suggest that the combination treatment of lactic acid and SHS can be used as an antimicrobial intervention for cantaloupes without inducing quality deterioration.

The Efficacy of Lactic Acid Immersion as an Antimicrobial Intervention in Beef Sub-Primal Fabrication

ObjectivesTo perform an in-plant validation of a lactic acid immersion (2–5%) intervention in 6 different subprimals on the fabrication floor.Materials and MethodsSwab samples (n = 324) were taken before and after intervention application from six different processing lines. Each subprimal had a 500 cm2 area swabbed using sterile materials. Each repetition included 18 samples per line, 9 before and 9 after intervention, for a total of 108 samples per repetition. Swab samples were immediately chilled and shipped overnight to the TTU Food Microbiology laboratory for microbial analysis. Samples were stomached at 230 rpm for 30 s and for each subprimal, 3 individual samples were composited into one. Serial dilutions were performed and 1ml of each composite was plated onto Enterobacteriaceae, aerobic plate count, Escherichia coli and coliform Petrifilms in duplicate. Counts were transformed into LogCFU/cm2 and statistical analysis was performed to determine differences between before and after treatment samples with a 0.05 probability threshold.ResultsMicrobial counts of all four microorganisms evaluated were significantly reduced (P < 0.05) after the lactic acid immersion (2–5%) intervention application in subprimals. Total coliform counts before and after treatment were 0.31 and 0.06 LogCFU/cm2, respectively. Enterobacteriaceae counts in the subprimals were in average 0.40 LogCFU/cm2 before interventions and 0.06 LogCFU/cm2 after intervention application. Overall aerobic plate counts were 1.77 LogCFU/cm2 before intervention and 1.14 LogCFU/cm2 after intervention. Generic E. coli counts after intervention were lower than the detection limit (< 1 CFU/20 cm2).ConclusionBased on data collected, it is reasonable to conclude that the lactic acid immersion intervention is effective in reducing common microbial indicators on subprimals inside the fabrication floor, improving the safety of the product.

Visualisation of insect tracheal systems by lactic acid immersion.

The endeavours to reveal the tracheal system of insects and some arachnids has a long history. The traditional way to observe a tracheal system in an insect body is by utilising the glycerin immersion method. In this study, we developed the lactic acid immersion method, which reveals a more complete tracheal system. By mounting various types of live specimens or body parts directly into lactic acid, multiple intact and complex tracheal systems were clearly visualised. The lactic acid immersion contributed to revealing tracheal systems by penetrating body tissue while reserving enough time for observation before the penetration of the tracheae. Preliminary comparisons were conducted between lactic acid and other mediae, including glycerin. It turned out that lactic acid immersion provides better details and more distinct structures. In our test, the optimal time for observing the tracheal system was 10-25 min after the organism was immersed in lactic acid.

Corrosion of laser-welded stainless steel orthodontic wires

PurposeFabricating orthodontic appliances using laser welding has the clinical advantage of biocompatibility, because the welded joint does not require soldered alloy. The purpose of this study was to investigate the corrosion of laser-welded stainless steel wires in acidic environments. Materials and methodsLaser welding of stainless steel wires with a 0.021×0.025 in cross-section was performed at an energy output ranging from 0.5 to 1.3kW. A control sample was prepared using conventional soldering. The samples were immersed in 1% lactic acid aqueous solution for 7 days. After immersion, the concentrations of metallic ions in solution were measured using inductively coupled plasma atomic emission spectroscopy. Tensile loading tests were carried out with and without lactic acid immersion. Scanning electron microscopy was used to examine the microstructure of laser-welded samples. ResultsThe concentrations of metallic ions detected in solution for laser-welded samples were significantly lower than that for soldered sample. There was no significant difference among the mean tensile strengths with and without immersion for laser-welded samples. The penetration depth and the localized region fused by laser irradiation increased with energy output, and ductile fractures were observed in the fused region of laser-welded samples. ConclusionLaser welding of stainless steel orthodontic wires should be acceptable for clinical use, because the joints showed sufficient strength and the original structure was not significantly altered. Immersion in acidic solution had minimal effect on the mechanical performance at the joint regions, and showed minimal acceleration of metallic ion release.

Bacterial adhesion not inhibited by ion-releasing bioactive glass filler

ObjectiveBioactive glasses and surface pre-reacted glass-ionomer (sPRG) filler possess cariostatic properties owing to ion release. Many studies investigated potential cariostatic effects; few studies evaluated the surface stability and the structural changes their surfaces undergo in acidic conditions. MethodsThe surface resistance against acid attack and the surface receptiveness for bacterial adhesion and biofilm formation of a sPRG-filled (Beautifil ll, Shofu) and conventional glass-filled (Herculite XRV Ultra, Kerr) resin-based composite (RBC), and a conventional glass-ionomer cement (GIC; Fuji IX GP Extra, GC) were examined. Specimens (n=3) were immersed in distilled water or lactic acid (pH 4.0) for 3 days. Bacterial growth and biofilm formation were recorded using optical density and SEM. ResultsUpon 3-day immersion in lactic acid, the surface of the sPRG-filled RBC revealed multiple holes, while virtually no change in surface integrity was observed for the conventional RBC and GIC. Bacterial growth measurements revealed that none of the materials inhibited Streptococcus mutans (p<0.05). Remarkably, cross-sectional SEM revealed that S. mutans had penetrated the etch pits induced by lactic acid in/around the sPRG filler. Ion-release measurements revealed that sPRG-filled RBC released boron and fluoride, while GIC only released fluoride. However, the concentration of ions released by both materials appeared not sufficient to inhibit bacterial growth. Moreover, the structural surface change and resultant increased surface roughness appeared to have promoted biofilm formation. SignificanceWhile having bioactive potential through ion release, the stability of surface integrity of bioactive materials is a key-parameter to be assessed with regard to their cariostatic potential.

Long-term degradation of resin-based cements in substances present in the oral environment: influence of activation mode

Indirect restorations in contact with free gingival margins or principally within the gingival sulcus, where the presence of organic acids produced by oral biofilm is higher, may present faster degradation of the resin-based cement pellicle.Objectives:To investigate the degradation of four resin-based cements: Rely X ARC (R), Variolink II (V), enforce (E) and All Cem (A), after immersion in distilled water (DW), lactic acid (LA) and artificial saliva (AS) and to analyze the influence of the activation mode on this response.Material and Methods:Two activation modes were evaluated: chemical (Ch) and dual (D). In the dual activation, a two-millimeter thick ceramic disk (IPS empress System) was interposed between the specimen and light-curing unit tip. Specimens were desiccated, immersed in distilled water, artificial saliva and lactic acid 0.1 M at 37ºC for 180 days, weighed daily for the first 7 days, and after 14, 21, 28, 90 and 180 days and were desiccated again. Sorption and solubility (µg/mm3) were calculated based on ISO 4049. The data were submitted to multifactor analysis of variance (MANOVA) and Tukey's HSD test for media comparisons (α=0.05).Results:Sorption was higher after immersion in LA (p<0.05) and increased significantly with time (p<0.05). Sorption was influenced by the activation mode: Ch>D (p<0.05). The lowest solubility was presented by R (p<0.05). Conclusions:Lactic acid increased the degradation of resin-based cements. Moreover, the physical component of activation, i.e., light-activation, contributed to a low degradation of resin-based cements.

Laktik Asit ve Kitosanın Soğukta Muhafaza Edilen Midyelerdeki Kalite Değişiklikleri Üzerine Etkileri

Laktik Asit ve Kitosanın Soğukta Muhafaza Edilen Midyelerdeki Kalite Değişiklikleri Üzerine Etkileri

Sorption and solubility characteristics of self-adhesive resin cements

ObjectiveThe aim of this in vitro study was to evaluate some sorption characteristics [sorption (S), solubility (SL) and the percentages of mass change (Mg%), solubility (SL%) as well as sorbed liquid (S%)] of self-adhesive resin cements when immersed in distilled water and lactic acid. MethodsA disc-shaped specimen of each self-adhesive resin cements [G-Cem (GC), SmartCem™ 2 (SC2), RelyX™ U100 (R1), RelyX™ Unicem 2 (RU2)] were prepared in a split-Teflon mold and irradiated by an Optilux 501 light cure at 580mW/cm2 for 40s in eight overlapping sections each side. The volume of each specimen was calculated and placed inside a desiccator containing anhydrous calcium chloride, then weighed on an analytical electronic balance. Two independent groups were established according to the immersion media or liquids (distilled water and 0.01M lactic acid) maintained at 37°C for the time intervals: 1, 6, 12, 24, 48 and 168h, where the sorption (S) property (μg/mm3) was calculated. However, the SL, Mg%, SL% and S% were measured after 168h of immersion. The data were statistically analyzed by repeated measures ANOVA, one-way ANOVA and post hoc Tukey's test (p<0.05). ResultsAnalysis of variance revealed highly significant differences between the materials for the sorption and solubility values examined with some exceptions (p<0.05). However, independent samples T-test expressed significant differences of all the sorption values between both water and lactic acid media for the resin cements with some border significances (p>0.05). The highest liquid's sorption was exhibited by GC material after immersion in lactic acid for 168h period followed by SC2 (37.83 and 34.15μg/mm3, respectively), while the lowest sorption was presented by RU2 cement after 1h immersion period in water (3.89μg/mm3). Stereomicroscope showed homogenous surface topography in RU2 and R1 samples, while some striated cracks and microvoids were observed in GC and SC2 materials, respectively. The SL values followed this order: RU2<R1<SC2<GC. SignificanceKnowing the best self-adhesive cement that can provide less sorption and solubility values will help the dentist to choose the most suitable luting material for indirect restorations.

Validation of a 2 percent lactic acid antimicrobial rinse for mobile poultry slaughter operations.

Poultry processing antimicrobial interventions are critical for pathogen control, and organic, mobile operations in Washington seek alternatives to chlorine. Laboratory and field studies (three replications each) evaluated lactic acid efficacy as a chlorine alternative. For the laboratory study, retail-purchased, conventionally processed chicken wings inoculated with Salmonella were randomly assigned to the following treatments: Salmonella inoculation followed by no treatment (10 wings) or by 3-min rinses of water, 50 to 100 ppm of chlorine, or 2% lactic acid (20 wings for each rinse treatment). Wings were sampled for Salmonella enumeration on xylose lysine desoxycholate agar. During pastured poultry processing at mobile slaughter units for each field study replication, 20 chicken carcasses were randomly assigned to each treatment: untreated control or 3-min immersion in lactic acid or chlorine. Whole-carcass rinses were examined for aerobic plate count (APC) on tryptic soy agar and coliforms on violet red bile agar. Untreated controls were also examined for Salmonella. In the laboratory study, lactic acid produced a significant (P < 0.01) Salmonella reduction compared with the inoculated no-rinse, water, and chlorine treatments, which were statistically similar to each other. In the field study, no Salmonella was detected on untreated controls. Lactic acid produced significant >2-log (P < 0.01) reductions in APC and coliforms, whereas chlorine resulted in slight, but significant 0.4-log reductions (P < 0.01) and 0.21-log reductions (P < 0.05) in APC and coliforms compared with untreated controls. Considering laboratory and field studies, lactic acid produced greater reductions in Salmonella, APC, and coliforms, validating its effectiveness as a chlorine alternative in mobile poultry slaughter operations.

Interaction between GIC and S. sanguis biofilms: Antibacterial properties and changes of surface hardness

The aim of this study was to investigate the interaction of Streptococcus sanguis with two glass-ionomer formulations (GIC:A containing fluoride and GIC:B without fluoride) with particular reference to bacterial growth and changes in hardness of the cement with respect to time. Discs of two water activated glass-ionomer cements were prepared according to the manufacturer's instruction. Hydroxyapatite discs (HA) were used as controls. 3D laser scanning technique was used to characterize surface roughness and area of the substrate prior to growing biofilms. Surface hardness was evaluated before and after biofilm growth. A constant depth film fermenter system (CDFF) was used to grow S. sanguis biofilms on the specimens in a similar manner to that described previously by Wilson et al. in 1995. For susceptibility measurement, specimens were removed from CDFF aseptically over periods up to 14d after the first colonization with bacteria. Counts of viable bacterial in the accumulating biofilm layer on each surface were measured and converted to colony forming units per unit surface area. To determine the effect of storage media, hardness discs were exposed to distilled water, lactic acid pH 4, lactic acid pH 5, citric acid pH 5, artificial saliva and S. sanguis biofilms. Twenty-four hours after preparing and subsequent autoclaving, specimens were transferred to a vessel containing 40 ml storage medium. The specimens were investigated for periods up to 7d. The viable counts of S. sanguis per mm2 on GIC:A were significantly less than those on HA and GIC:B during the first 5d (p<0.05). The viable counts of bacteria on the surface of GIC:B were lower during the initial 5d when compared to HA. Exposure of GIC:A and GIC:B to different medium produced softening to the surface of cement. It is apparent that the effects of the biofilms are significantly greater than storage in water but similar to storage in lactic acid pH 5. This investigation showed that the growth of S. sanguis biofilms were significantly affected by both glass-ionomer formulations, the greater reduction being noted on the surface of the fluoride containing GIC. S. sanguis biofilms produced reduction on the surface hardness of the cement equivalent to that seen after immersion in lactic acid at pH 5. This indicates that while S. sanguis biofilm is affected by the GIC, there is also a decrease in hardness of the cement indicating some cement degradation.

脱灰エナメル質の再石灰化に及ぼすレーザー照射ならびにフッ素の影響

The aim of this study was to evaluate the effect of the laser irradiation and the presence of fluoride in the remineralizing solution on the remineralization of deminalized enamel. The enamel of ninety human premolars was demineralized artificially. This was then irradiated with a Q-switch Nd-YAG laser and remineralized with two remineralizing solutions, one with and the other without fluoride. To evaluate the mineralized enamel, the mineral content of the enamel was calculated and two acid resistance tests (1. mineral content evaluation after HClO4 immersion, 2. dissolved Ca2+ measurement after lactic acid immersion) were performed.The results were as follows:1. In the acid resitance test with HClO4, the presence of fluoride in the remineralizing solution increased the acid resistance of the demineralized enamel.2. In the acid resistance test with lactic acid, 1) laser irradiation increased the acid resistance of the demineralized enamel, 2) the acid resistance effect of laser irradiation was the same as that of the presence of fluoride in the remineralizing solution, and3) the highest acid resistance was found in the combined treatment of laser irradiation and remineralization with fluoride.

The Fine Surface Structure of the Male Genital Bulb of the Dwarf Spider Catabrithorax Plumosus

The spider Catabrithorax plumosus (Emerton) family Linyphiidae, subfamily Erigoninae is a member of an abundant yet reclusive group known as the dwarf spiders. Collectively, these are the smallest spiders in North America. Most measure only 1-3 mm in length, creating difficulties in indentification. The morphology of the male genital bulb, located on the distal pedipalp, is of great importance to the taxonomist in identifying spiders to the species level. This study examines the complex male genital structure in both the expanded and unexpended condition by means of the Scanning Electron Microscope (SEM).Pedipalps were removed at the trochanter-femur articulation, dehydrated in 70% ethanol and expanded by Immersion in lactic acid for 6-8 h. After complete expansion a graded amyl acetate series preceeded critical point drying. Unexpanded palps were dehydrated in an ethanol series followed by a graded amyl acetate series in ethanol. Specimens were critical point dried from CO2 and given an evaporated coating of carbon-gold. Specimens were examined in a Hitachi HHS-2R Scanning Electron Microscope operating at an accelerating voltage of 10 kV.