State of antioxidative protection in central nervous ganglia of the mollusc <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> at modulation of activity of the NO-ergic system

In experiments on mollusc Lymnaea stagnalis, the state of antioxidative protection is studied in central nervous ganglia during a long-term activation (inhibition) of synthesis of nitrogen monoxide (NO) in the body. The effect of the blocker of NO-synthase N^G-nitro-L-arginine (L-NNA) at the background of enhancement of pulmonary respiration has been found to be associated with a rise of levels of reduced glutathione and TBK-active products in the nervous tissue at preservation of a relatively high superoxide dismutase activity and a low glutathione peroxidase activity compared with the control group and the animals treated with the metabolic precursor of NO synthesis L-arginine. In spite of the revealed disturbances of balance of the body proand antioxidative system, DNA electrophoresis detected no products of its degradation, which can indicate the absence of massive programmed death of the nervous tissue cells in Lymnaea stagnalis during modulation of activity of the NO-ergic system.     

Two Subtypes of Nicotinic Acetylcholine Receptors in <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> Neurons Control Chloride Conductance

Giant neurons of the mollusc Lymnaea stagnalis contain heterogeneous population of nicotinic acetylcholine receptors (nAChRs) according to their relative sensitivity to antagonists. All these receptors are involved in the total response to acetylcholine (ACh). To evaluate activity of different pharmacological agents correctly it is necessary to know ionic selectivity of nAChRs which participate in transmembrane ionic current. In this work we studied the influence of ionic composition of the external and intracellular solutions on the current amplitude and current–voltage relation under the action of ACh or other nAChR agonists on the identified neurons of the left and right parietal ganglia of Lymnaea. After non-permeable cation N-methyl-D-glucamine was completely substituted for external Na⁺ ions there were no changes in the current characteristics. After a 10-fold decrease in Cl–concentration in the external solution there was a considerable shift of the current–voltage curve to the right, outward currents at the holding potential (V_h) up to 30 mV were not observed. On the contrary, a 10-fold decrease of Cl^– concentration in the intracellular solution led to a shift of the current–voltage curve to hyperpolarizing direction, the reversal potential shift was in the average –42 mV. When ACh and nicotinic agonists with higher selectivity towards vertebrate α7 neuronal nAChR type and one of the two subtypes of Lymnaea nAChRs were compared, no differences in changes of ionic current characteristics were found. Neurons with distinct relative fraction of one or another nAChR subtype reacted to Cl^– concentration change in the same way. Our results support earlier data on Cl^– mechanism of Lymnaea neuron responses to ACh and evidence identical ionic selectivity of the two nAChR subtypes in identified neurons tested.     

Resistance to herbivory of two populations of <Emphasis Type="Italic">Elodea</Emphasis><Emphasis Type="Italic">canadensis</Emphasis> Michaux and <Emphasis Type="Italic">Elodea nuttallii</Emphasis> Planchon St. John

In this article, we compared the resistance of two introduced populations of Elodea nuttallii and Elodea canadensis to two different herbivores. Samples were collected from the River Rhine and River Rhône in eastern France. The two populations of E. nuttallii differed in their introduction history, whereas E. canadensis was introduced at the same time in the two sites. The Daily Food Consumption (DFC) rates of the two macrophyte populations were evaluated in no-choice experiments using the scraper Lymnaea stagnalis and the shredder Gammarus roeseli. At the same time, we assessed four plant traits: dry matter content (DMC), total nitrogen content, carbon/nitrogen ratio and total phenolic content. The two populations of E. canadensis were consumed at low levels by both the herbivores. L. stagnalis showed a higher DFC on the Rhône population of E. nuttallii than on the Rhine population. No significant difference between the two populations was established with G. roeseli, but the level of DFC was high. This result demonstrates that the assessment of plant palatability should be carried out with several generalist herbivores belonging to various feeding groups (e.g. scrapers or shredders). Although the Rhône population of E. nuttallii had higher levels of phenols than the other populations, it was consistently consumed in greater quantities than E. canadensis. Neither the phenolic contents were not effective against these herbivores, nor the levels of phenolics too low to induce an efficient resistance. The higher DMC and the lower DFC of the two populations of E. canadensis suggest that this introduced plant has co-evolved with indigenous enemies in the introduced range.     

Cellular basis of temperature dependence of the food-procuring activity of the mollusc <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis>

Neuronal correlates of temperature dependence of alimentary behavior were studied in experiments on molluscs. It was found that a decrease of temperature led to suppression of food-procuring activity of the animals: to a decrease of the consumed food amount and of the number of food holes on the substrate. These behavioral changes are associated with a fall of impulsation frequency of the motoneuron alimentary network and with decrease of efficiency of synaptic transmission within the limits of central generator of the Lymnaea stagnalis alimentary rhythm. It is suggested that change of character of intercellular interactions within the CNS limits underlies the temperature dependence of the mollusc food-procuring activity.     

Effect of habitat and motor activity of molluscs on fatty acid composition of triglycerides and phospholipids

A comparative analysis of fatty acids (FA) in neutral lipids and phospholipids of digestive gland and pedal muscle has been performed in molluscs from various ecological groups differing by belonging to sea or fresh water, trophic types or the associated motor activity. In freshwater pulmonary gastropods Lymnaea stagnalis and Lymnaea ovalis and marine prosobranchial molluscs Buccinum undatum and Littorina littorea the total content of ω3-acids in phospholipids of the studied tissues differed more than twice, predominantly due to the combined effect of temperature and salinity of the habitat. The lower viscosity of cell membranes in marine species (ω3/ω6 < 1) is determined to the greatest degree by the presence of eicosapentaenoic acid that accounts for 22–25% of the FA sum in marine species. Comparison of the molluscs by their trophic belonging has revealed the presence of linoleic acid in triglycerides in digestive glands of phytophages (8–12%), but the practically complete absence of this acid in the predator B. undulatum (< 0.8%). By mobility, L. littorea inhabiting the high-low tide littoral was inferior to freshwater pulmonary gastropods and to the marine predator, as it stops moving twice a day during the low tide. In phospholipids of pedal muscle of this mollusc the amount of long-chain polyunsaturated C: 22 FA was 3–6 times lower than that in other studied species, which might possibly indicate the role of these acids in functioning of the pedal muscle contractile tissue. On the whole, use of the FA characteristics as the parameters determining belonging to certain ecological group requires a certain caution due to a complex action of biotic and abiotic factors on the animal metabolism. The exception is the ω3/ω6 ratio in total phospholipids of fresh water and marine gastropods.     

Temperature dependence of monoamine-induced pulmonary respiration in the mollusc <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis>

Pulmonary respiration (spontaneous and mediated by intracavitary administration of monoamines) has been studied in molluscs at different ambient temperatures (5, 15, and 25°C). Monoamines (dopamine, serotonin, and adrenaline) were established not to broaden the temperature diapason realization of the respiratory behavior. Microelectrode studies of the spontaneous electrical activity of the Lymnaea stagnalis respiratory network neurons (RPeD1, VD4, and Vi-cluster cells) revealed that both spontaneous and monoamine-induced respiration programs had been terminated under hypothermia conditions. The indicated effects are suggested to be due to the temperature dependence of the chemical, predominantly peptidergic, transmission of signal between neurons of the central respiratory rhythm generator in Lymnaea.     

Histological evidence that diploid hybrids of <Emphasis Type="Italic">Cobitis taenia</Emphasis> and <Emphasis Type="Italic">C. elongatoides</Emphasis> (Teleostei,Cobitidae) develop into fertile females and sterile males

Rising temperatures likely affect the trophic interactions in temperate regions as global warming progresses. An open question is how a temperature rise may affect consumer pressure and plant abundance in shallow aquatic ecosystems, where most consumers are omnivorous. Interestingly, herbivory (plant-eating) is more prevalent toward low latitudes in ectotherms such as fish and aquatic invertebrates, and this may be temperature driven. We used pond snails (Lymnaea stagnalis L.) as a model aquatic ectotherm species and tested their consumption of both animal prey (Gammarus pulex L.) and plant material (Potamogeton lucens L.) at three different temperatures (15, 20, and 25°C). Higher temperatures led to higher consumption rates by the omnivore on both plant food and animal prey when fed separately. When the food was offered simultaneously, the pond snails consistently preferred animal prey over plant material at all tested temperatures. However, the omnivore did consume plant material even though they had enough animal prey available to them. Based on our experiments, we conclude that with increasing temperatures, L. stagnalis will only increase their consumption rates but not change food preference. Further studies are needed to test the generality of our findings across aquatic species to predict the effect of warming on aquatic plant consumption.     

Susceptibility of germinating cruciferous seeds to <Emphasis Type="Italic">Bagrada hilaris</Emphasis> (Hemiptera: Pentatomidae) feeding injury

Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae) is a serious pest that attacks both germinating and seedling stages of a variety of cruciferous crops grown in the Central Coast of California. B. hilaris feeding on germinating seeds can cause severe stunting and plant mortality, and little is known about the feeding preference of B. hilaris for germinating seeds of major cruciferous hosts and varieties of hosts. No-choice and choice experiments were conducted in which germinating seeds in soilless and soil settings were exposed to B. hilaris adults for 7 days. Susceptibility scores were developed using B. hilaris feeding injury sites, distorted leaves, and deformed and dead plants to determine the overall B. hilaris preference for germinating host seeds. Based on the scores, the order of preference was arugula (Eruca sativa L.)?>?turnip (B. rapa L. var. rapa)?>?mizuna (B. rapa L. nipposinica)?>?kale (B. oleracea L. acephala)?>?choi (Brassica rapa L. var. chinensis)?>?broccoli (B. oleracea var. italica Plenck)?>?cauliflower (B. oleracea L. var. botrytis)?>?lettuce (Lactuca sativa L.)?>?sweet alyssum (Lobularia maritima [L.] Desv.). The lowest feeding injury was recorded on germinating lettuce and sweet alyssum seeds. Furthermore, no-choice and choice experiments were conducted with four varieties each of arugula and mizuna, twelve varieties each of kale and choi, and nine varieties/types of leafy Asian greens. The arugula varieties ‘Wild Rocket’ and ‘Spirit’ were more damaged by B. hilaris than other varieties tested. Among mizuna varieties, ‘Beira F1’ was more attractive to B. hilaris than ‘Scarlet’ or ‘Starbor F1.’ The choi varieties ‘Tokyo Bekana,’ ‘Feng Qing Choi F1,’ ‘Joi Choi F1,’ and ‘Win-Win Choi F1’ were more attractive than ‘Rosie F1.’ The leafy Asian greens variety ‘Carlton F1’ was more attractive to B. hilaris than ‘Yukina Savon,’ ‘Tatsoi OG,’ ‘Komatsuna Summerfest F1,’ ‘Red Rain F1,’ and ‘Shungiku.’ Therefore, the results suggest that not all varieties were equally susceptible to B. hilaris feeding and possibly be utilized for further field evaluation as a trap crop or developing more resistant varieties to B. hilaris.     

Larval identification of two syntopic species <Emphasis Type="Italic">Branchipus schaefferi</Emphasis> and <Emphasis Type="Italic">Tanymastix stagnalis</Emphasis> (Crustacea,Anostraca) sheds light on their pattern of coexistence

In the present study we applied a discriminant function analysis to distinguish two fairy shrimp species, Branchipus schaefferi and Tanymastix stagnalis (Anostraca), co-occurring in Lago dell’Orso in central Italy. Our aim was to obtain information on the pattern of coexistence of these two species to investigate their syntopy since early larval stages. To identify the larvae of the two species we used six discriminant functions, one for each larval stage considered (nauplius, four metanauplius stages and juvenis), and based on morphometric analyses and measurements of different traits (thoracic appendages, body length, length of first antenna, length of head, thorax length and length of furca). The pool was visited at weekly intervals during two time periods for a total of 4 years (1995–1996 and 2000–2001) and physical and chemical variables (water level, water and air temperature, pH and conductivity) were recorded. A total of 1067 specimens were collected, measured and morphometrically identified. B. schaefferi was more abundant and persistent than T. stagnalis. At any stage, T. stagnalis was bigger than B. schaefferi and this difference may justify niche differentiation between coexisting species. Difference in size might be linked to difference in life-span as B. schaefferi reproduced earlier and at a smaller size than T. stagnalis. When the hydroperiod is short, B. schaefferi might be the only species to produce resting eggs in time for reproduction. On the other hand, T. stagnalis may have an advantage in the longest hydroperiods. In an ephemeral seasonal pond such as Lago dell’Orso, coexistence can be fostered and competitive exclusion can be prevented as a result of seasonal environmental changes.     

NADPH-diaphorase activity in the digestive system of gastropod molluscs <Emphasis Type="Italic">Achatina fulica</Emphasis> and <Emphasis Type="Italic">Littorina littorea</Emphasis>

Distribution and morphological peculiarities of nitroxidergic elements throughout the entire length of digestive tract was studied for the first time in gastropod molluscs Littorina littorea (Prosobranchia) and Achatina fulica (Pulmonata) using histochemical detection of NADPH-diaphorase (NADPHd). NO-ergic cells and fibers were revealed in all parts of the mollusc digestive system beginning from esophagus. Intensive NADPHd activity is found in a great number of intraepithelial cells of the open type and their processes in the intraand subepithelial nerve plexuses, subepithelial neurons, granular connective tissue cells, and multiple nervous fibers distributed among muscular elements of digestive tract as well as those in nerves innervating the tract. NADPHd was also revealed in receptor cells in the oral area and in the A. fulica CNS ganglia innervating the digestive tract. A. fulica has a more complicated organization of A. fulica nitroxidergic system of the digestive tract. A system of glomerular structures formed by thin NADPHd-positive neural fibers coming from epithelium is found directly beneath the epithelium in esophagus, stomach, and midgut of the mollusc. More superficially under the main groups of muscular elements there are revealed small clusters of NADPHd-positive neurons that can be classified as primitive, non-structured microganglia. The distribution pattern and a possible functional role of nitroxidergic elements in digestive tract of molluscs as compared with other invertebrate and vertebrate animals are discussed.     

Distribution and quantitative characteristics of common species of pond snails of the subgenera <Emphasis Type="Italic">Peregriana</Emphasis> and <Emphasis Type="Italic">Radix</Emphasis> (Mollusca: Gastropoda: Lymnaeidae) in waterbodies of the south of Western Siberia

Information on some ecological features of eight species of pond snails belonging to the subgenera Peregriana and Radix (Lymnaea ampla (Hartmann), L. ampullacea (Rossmässler), L. auricularia (L.), L. balthica (L.), L. fontinalis (Studer), L. lagotis (Schrank), L. ovata (Draparnaud), and L. tumida (Held)) in the waterbodies of south of Western Siberia is presented. The patterns of the species distribution and their cooccurrence in different waterbodies have been studied. An analysis of the quantitative variables (abundance and biomass) of the snails in the waterbodies of the Karasuk lake-river system and in the Novosibirsk Reservoir has been performed.     

Biochemical strategy of survival of the freshwater mollusc <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> at near-zero temperatures

Effect of an autumn-winter decrease of the environmental temperature on changes of the content of free amino acids and reducing sugars was studied in tissues fluids of the freshwater mollusc L. stagnalis. At a decrease of the temperature to 4 and 0°C at the autumn period, concentration of free alanine rose several times; an increase of histidine, glutamate, glycine, and serine concentrations was less pronounced. Accumulation of methionine, leucine, isoleucine, tyrosine, and phenylalanine was revealed at 0°C. In the state of long hypobiosis (at 4°C), pools of all amino acids fell 4–8 times; essential amino acids, except for lysine, were not detected at all. Both at the summer and at the autumn periods, high concentrations of free fructose and glucose were revealed. In the process of hypobiosis the fructose pool decreased almost 35, while the glucose pool—12 times. Maltose that was absent in summer was found at 4 and 0°C as well as after 2.5 months of hypobiosis. The changes of the studied parameters in L. stagnalis in response to hypothermia are compared with the corresponding parameters of changes in cryoresistant animals in response to negative temperatures.     

Role of chemical signalling in release of motor programs during embryogenesis of freshwater snails <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> and <Emphasis Type="Italic">Helisoma trivolvis</Emphasis>

We have earlier found that freshwater pond snails Helisoma trivolvis and Lymnaea stagnalis, when reared under conditions of starvation, release chemical signals that reversibly suppress larval development of conspecific embryos. Here, we report that (i) these signals are not strictly conspecific and affect also the embryos of a closely related species, which occupies a similar environmental niche; (ii) besides the development of embryos, the signals also affect the release of main motor programs, such as locomotion, feeding, and cardiac activity; (iii) action of the signals is bidirectional: they retard the development and release of motor programs at the early larval stages (trochophore to veliger) and accelerate them at later stages (late veliger to hatching). A possible adaptive significance of the described phenomena is discussed.     

Effects of alien invasion by <Emphasis Type="Italic">Bombus terrestris</Emphasis> L. (Apidae) on the visitation patterns of native bumblebees in coastal plants in northern Japan

When alien pollinator species enter a native community of pollinators in which resource partitioning has been established, the pollination network between plants and pollinators may be modified through the interactions between the pollinators over the use of floral resources. We observed the floral-use patterns of native (Bombus hypocrita and B. deuteronymus) and alien (B. terrestris) bumblebee species in a coastal grassland in northern Japan. We analyzed the factors determining resource partitioning patterns. B. hypocrita tended to visit flowers with shallow or wide open corollas, such as Rosa rugosa, whereas B. deuteronymus visited flowers with complex or deeper corollas, such as Lathyrus japonicus. Given the wider floral preference of B. terrestris, floral use by the alien bumblebees consistently overlapped with that of native bumblebees. The visitation of B. terrestris to R. rugosa flowers was positively correlated with that of B. hypocrita. These bumblebee species frequently used similar floral resources, in part because of the large overlap in the seasonality of their foraging activity. The visitation frequency of B. deuteronymus to L. japonicus flowers was independent of the visitation frequency of other bumblebee species. The major visitation periods of the bumblebees to L. japonicus flowers reciprocally differed between B. deuteronymus and B. terrestris, suggesting phenological resource partitioning between these species. Our study suggests that phenological niche partitioning is more common in specialized flowers (L. japonicus) than in generalized flowers (R. rugosa).     

New paradoxical three-finger toxin from the cobra <Emphasis Type="Italic">Naja kaouthia</Emphasis> venom: Isolation and characterization

A new three-finger toxin nakoroxin was isolated from the cobra Naja kaouthia venom, and its complete amino acid sequence was established. Nakoroxin belongs to the group of “orphan” toxins, data on the biological activity of which are practically absent. Nakoroxin shows no cytotoxicity and does not inhibit the binding of α-bungarotoxin to nicotinic acetylcholine receptors of muscle and α7 types. However, it potentiates the binding of α-bungarotoxin to the acetylcholine-binding protein from Lymnaea stagnalis. This is the first toxin with such an unusual property.     

Food web interactions determine energy transfer efficiency and top consumer responses to inputs of dissolved organic carbon

The sand stored in the gizzard of some freshwater snails should assist in the mechanical digestion of tough food, yet effects of gizzard sand on consumption of living macrophyte tissue are seldom addressed. We quantified the effects of gizzard sand both on consumption of plant tissue and on snail growth and reproduction with a cross-gradient, 28-day laboratory experiment. We offered apical shoot sections of Myriophyllum spicatum (initial ash content ~ 56%) or soft lettuce (ash content ~ 19%, as control) to Lymnaea stagnalis previously reared on sand or without sand. Gizzard sand had no effect on snail growth but sand-reared snails fed with lettuce initially produced more eggs than their no-sand counterparts. Snails fed M. spicatum exhibited stunted growth and produced only one small egg clutch. Shell height at time of first oviposition of M. spicatum-fed snails was two-thirds of that of lettuce-fed controls. Snails initially appeared to feed on periphyton and older, brownish M. spicatum leaflet tips, but later turned to midstem tissue. Fresh apices were not consumed. Gizzard sand had a limited effect on the ability of L. stagnalis to consume living M. spicatum, with apices likely defended chemically (polyphenols) and midstem tissue defended structurally (high ash content).     

On the problem of retinal transmitters of the freshwater mollusc <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis>

Retrograde staining of retina of Lymnaea stagnalis with neurobiotin demonstrated that most photoreceptor cells send axons to the optic nerve directly, without intermediate contacts. Some of the photoreceptors are glutamate-immunoreactive suggesting that glutamate can provide the synaptic transmission of visual signal to the central neurons. Other photoreceptors stained via optic nerve seem to have other transmitter systems. Some of the retinal cells, but not the optic nerve fibers are pigment-dispersing hormone-immunoreactive. There are many serotonin-containing fibers in the tissue surrounding the optic cup with some of them penetrating the basal lamina of retina. Some of them belong to central neurons providing efferent innervation of the pond snail eye. Serotonergic innervation as well as pigment-dispersing hormone-containing cells are supposed to be involved in mechanism of the photosensitivity regulation of the molluscan eye.     

Structure of visual pathways in the nervous system of freshwater pulmonate molluscs

Central nervous system of freshwater pulmonate molluscs Lymnaea stagnalis and Planorbarius corneus was stained using retrograde transport of neurobiotin in the optic tract fibers. In both species, perikarya and fibers of the stained neurons are found in all ganglia except the buccal ones. Afferent fibers of the optic nerve form dense sensory neuropil located in relatively small volume of cerebral ganglia. Typical neuronal groups sending their processes into the optic nerves of ipsilateral and contralateral body halves are described. Among them, neurons of visceral and parietal ganglia innervating both eyes concurrently as well as sending projections into peripheral nerves are revealed. These neurons, supposedly, have a function to integrate sensory signals, which may be a basis for regulation of light sensitivity of retina and functioning of peripheral organs. Bilateral links of the molluscan eye with the pedal ganglia cells and statocysts are found, which is, likely, a structural basis of certain known behavioral patterns related to stimulation of visual inputs in the studied gastropod molluscs.     

Impact of the invasive painted bug <Emphasis Type="Italic">Bagrada hilaris</Emphasis> on physiological traits of its host <Emphasis Type="Italic">Brassica oleracea</Emphasis> var botrytis

Bagrada hilaris is a herbivorous insect native of Asia and Africa, which has invaded southern Europe and North America where it causes major damage to cole crops. Laboratory experiments were conducted to assess how the infestation of this invasive species damages the host Brassica oleracea var botrytis, and to evaluate the interaction between plant emission of volatile organic compounds (VOC) and B. hilaris adults. Plant responses to insect feeding were evaluated through changes in photosynthesis, stomatal conductance, VOC emission, and visual damage on leaves. The impact of B. hilaris was compared with that of Nezara viridula, a polyphagous species distributed worldwide. Plant VOC role in host plant detection was tested with electroantennography bioassays on B. hilaris antenna. Photosynthesis and stomatal conductance were consistently reduced in plants infested with 40 B. hilaris adults for 24 h. The feeding activity of a single B. hilaris caused larger discolored spots on host leaves in comparison with N. viridula. VOC emitted by B. oleracea changed significantly in response to B. hilaris and N. viridula infestation. In particular, production of limonene was strongly reduced by the infestation of the two pentatomids, while an increase in the emission of acetic acid and 2-ethyl-1-hexanol was observed. EAG dose–response tests using the main plant VOC showed B. hilaris antennal responses to benzaldehyde, octanal, nonanal, and acetic acid, which indicates a role of these compounds in host location.     

Enterocin B3A-B3B produced by LAB collected from infant faeces: potential utilization in the food industry for <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> biofilm management

Enterococcus faecalis B3A-B3B produces the bacteriocin B3A-B3B with activity against Listeria monocytogenes, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium perfringens, but apparently not against fungi or Gram-negative bacteria, except for Salmonella Newport. B3A-B3B enterocin has two different nucleotides but similar amino acid composition to the class IIb MR10A-MR10B enterocin. B3A-B3B consists of two peptides of predicted molecular mass of 5176.31 Da (B3A) and 5182.21 Da (B3B). Importantly, B3A-B3B impeded biofilm formation of the foodborne pathogen L. monocytogenes 162 grown on stainless steel. The antimicrobial treatment of stainless steel with nisin (1 or 16 mg ml^?1) decreased the cell numbers by about 2 log CFU ml^?1, thereby impeding the biofilm formation by L. monocytogenes 162 or its nisin-resistant derivative strain L. monocytogenes 162R. Furthermore, the combination of nisin and B3A-B3B enterocin reduced the MIC required to inhibit this pathogen grown in planktonic or biofilm cultures.